Single-rail vs. multi-rail power supplies?

[Yousuf Khan]

I currently have a desktop with a Zalman 600W PS, it was a pretty nice
PS a few years ago when I got it, but now it looks like the system has
been upgraded and grown again, and I'm starting to see signs that it's
not producing enough power for the components anymore. So I'm looking at
the market for bigger PS's, likely 750W+.

When I got the Zalman, multi-rail +12V were the de riguer feature of the
day. Now that I'm shopping for them again, I see that the manufacturers
have done an about-face, and they are advertising the advantages of
single-rail +12V. The old 600W had 4 rails at 16 Amps each. The new
single rails I'm seeing seem to have a rail at anywhere from 45A to 65A!
Why have the manufacturers done the about-face on single-rail vs.
multi-rail?

Yousuf Khan

[Paul]

That's a good question.

The terminology is adjusted, to whatever sells power supplies.
That's a rule of thumb about marketing. You don't actually
have to be honest about what you're selling. You describe it
in any way, that will make you successful. if a competitor
touted single rail output, and he's selling supplies,
then you chime in with a matching story.

These are some examples of power supply designs.

AC ---- switcher --- 65A ---- 75A_limiter ----+---- 12V1
|
+---- 12V2
|
+---- 12V3

OK, let's take a Molex, and short +12V to ground on that one.
The whole yellow and black wires on the Molex, start to glow,
the plastic melts off the wire, and so on. While this is a
"true single rail" design, notice it's a safety hazard. The
design could provide around 12*75 = 900W of thermal energy,
if you adjusted the loading just right. If the short had a
resistance of 0.2 ohms, the supply likely wouldn't shut off.
A dead short, might trip it OK. Hard to guess...

Now, let's make a design closer to the intentions of the
IEC60950 spec, and limit individual outputs to a safer level.
This still isn't compliant, but its closer to the spirit
of the limitations you're supposed to apply to secondary outputs.

AC ---- switcher ----- 65A ---+-- 25A_limiter --------- 12V1
|
+-- 25A_limiter --------- 12V2
|
+-- 25A_limiter --------- 12V3

Now, the wires may still get hot, the connectors burn, but
the amount of power in any individual circuit, cannot exceed
12*25 = 300W. The limiter works, by switching off the supply,
if the current flow level is exceeded. An overload in any
branch, can switch it off.

Power supplies built as follows, are "true independent output"
circuits. A hint you're getting the real McCoy, is the chassis
is 1" to 1.5" longer than the competing power supply of the
same capacity. The density cannot be as great, because of
the replicated circuits. I don't think that many, were
actually built this way. If you open your Zalman, it probably
doesn't match this topology. Your Zalman, might be the
previous figure.

AC -- DC ---+-- switcher ----- 22A ------ 25A_limiter --- 12V1
300V |
+-- switcher ----- 22A ------ 25A_limiter --- 12V2
|
+-- switcher ----- 22A ------ 25A_limiter --- 12V2

I'd say that middle design, looks pretty good. No matter
whether my marketing department describes it as "one rail"
or "multi rail". The size of the supply, or the lack of
replicated circuits inside, can help you judge the
true topology.

I don't own a copy of IEC60950, so I can't copy/paste
the appropriate part. And the last time I looked, I couldn't
find a copy "floating" on the web. The keyword "SELV" comes
to mind, but that's about all I remember now.

HTH,
Paul

[Rod Speed]

Yousuf Khan wrote

> I currently have a desktop with a Zalman 600W PS, it was a pretty nice PS a few years ago when I got it, but now it
> looks like the system has been upgraded and grown again, and I'm starting to see signs that it's not producing enough
> power for the components anymore.

What signs are those exactly ?

That wouldnt normally be the case unless you have one hell of a video card in it.

> So I'm looking at the market for bigger PS's, likely 750W+.

> When I got the Zalman, multi-rail +12V were the de riguer feature of the day. Now that I'm shopping for them again, I
> see that the
> manufacturers have done an about-face, and they are advertising the
> advantages of single-rail +12V. The old 600W had 4 rails at 16 Amps each.

And I would be amazed if you are exceeding that.

> The new single rails I'm seeing seem to have a rail at anywhere from 45A to 65A!

And even the biggest is only 1A more than you currently have.

> Why have the manufacturers done the about-face on single-rail vs. multi-rail?

So they dont have to have 4 separate 12V regulators.

[Rob]

Well get yourself one that has good weight and a three year warranty.

Bigger is not necessarily any better and depends on your PC configuration.

[Yousuf Khan]

On 21/03/2012 6:34 PM, Rod Speed wrote:
> Yousuf Khan wrote
>
>> I currently have a desktop with a Zalman 600W PS, it was a pretty nice PS a few years ago when I got it, but now it
>> looks like the system has been upgraded and grown again, and I'm starting to see signs that it's not producing enough
>> power for the components anymore.
>
> What signs are those exactly ?

Well, we've discussed those on csiphs already, mainly the optical drives
sending controller error messages even when they are not being used, and
I'm also noticing some occasional spin retry errors on a few of my
internal HDD's.

> That wouldnt normally be the case unless you have one hell of a video card in it.

Well, the video card is not a monster of any kind, it's more upper
mainstream, an AMD Radeon 6870.

>> So I'm looking at the market for bigger PS's, likely 750W+.
>
>> When I got the Zalman, multi-rail +12V were the de riguer feature of the day. Now that I'm shopping for them again, I
>> see that the
>> manufacturers have done an about-face, and they are advertising the
>> advantages of single-rail +12V. The old 600W had 4 rails at 16 Amps each.
>
> And I would be amazed if you are exceeding that.

Well, I ran my system components through a few power supply calculators:

http://extreme.outervision.com/PSUEngine said I needed 580W.
http://www.thermaltake.outervision.com/Power said I needed 574W.
http://support.asus.com/powersupply.aspx said I needed 900W!!!

Obviously, the Asus rating is an outlier so I'm ignoring that one, but
the other two seem to agree pretty close to each other, and that level
is pretty close to the maximum power rating (within 96-97%) of my old
PS. And with the age of the PS advancing in years, its maximum capacity
might actually be decreasing over time.

When I first obtained this 600W PS, the PS calculator showed that my
system requirement was only in the upper 400W range. So I thought I had
more than enough leeway, but it looks like the various upgrades have
quickly taken up most of that leeway since then.

>> The new single rails I'm seeing seem to have a rail at anywhere from 45A to 65A!
>
> And even the biggest is only 1A more than you currently have.

When you add it up, yes the 4 separate rails come out to about 64A, but
the point is is it possible that some of the rails are overloaded by
themselves? Would it be easier to distribute the power if there was a
single larger rail rather than 4 smaller rails?

>> Why have the manufacturers done the about-face on single-rail vs. multi-rail?
>
> So they dont have to have 4 separate 12V regulators.

I found one possible explanation here:

http://www.overclock.net/t/88626/info-do-you-need-multiple-12v-rails

According to the above, the EU had mandated that no single +12V rail
could exceed 20A, and that later Intel also embraced that EU rule, and
further reduced that down to 18A. But now it looks like Intel no longer
requires the 18A rule. I'm not sure if the EU has also dropped its 20A
requirement, but here in North America there is no longer a need to have
separate rails anymore, so we can go to single super-rails.

Yousuf Khan

[Grant]

Multi-rail was a cheap way to produce the high power, but it limits
the distribution of that power into defined loads, loads that the user
would perhaps not be able to judge correctly.

Single rail makes distributing the 12V a 'don't care' as far as splitting
up the load to suit the power supply. Much simpler, more efficient.

Grant.
>
> Yousuf Khan

[Paul]

Yousuf Khan wrote:

>
> Well, I ran my system components through a few power supply calculators:
>
> http://extreme.outervision.com/PSUEngine said I needed 580W.
> http://www.thermaltake.outervision.com/Power said I needed 574W.
> http://support.asus.com/powersupply.aspx said I needed 900W!!!
>
> Obviously, the Asus rating is an outlier so I'm ignoring that one, but
> the other two seem to agree pretty close to each other, and that level
> is pretty close to the maximum power rating (within 96-97%) of my old
> PS. And with the age of the PS advancing in years, its maximum capacity
> might actually be decreasing over time.
>
> When I first obtained this 600W PS, the PS calculator showed that my
> system requirement was only in the upper 400W range. So I thought I had
> more than enough leeway, but it looks like the various upgrades have
> quickly taken up most of that leeway since then.

The HD6870 is 124 to 147 watts. One of the cards quoted here could be
an overclock. Try doing your power calculation manually.

http://www.xbitlabs.com/articles/graphics/display/asus-eah6870-directcu_4.html#sect0

Paul

[KR]

Traditionally it was always considered good practice to separate the
power for
digital and analog circuits as much as possible to prevent
interference.
This would especially be the case in audio systems.

In the case of a PC, this would mean keeping the supply for motors
(such as
Hard Drives, CD ROMS etc on a separate circuit, so as to minimise any
electrical
noise from these from interfering with digital circuits - assuming
this really is a problem in a modern PC.

Usually having separate supply cables from a common power source is
sufficient.



I would suggest it is more likely done to keep the currents manageable
on particular circuits however.
You might have 60A available, but in cases like this where one circuit
is never going to need more than (say) 15a,
it is safer to split it into 4 separate circuits.

Exactly the same is done in your home fusebox in having separate fuses
and circuits for your lights, power points,
air con, water heater, stove etc, rather than just having a single
200A fuse for the entire lot.

[Rod Speed]

Yousuf Khan wrote

> Rod Speed wrote
>> Yousuf Khan wrote

>>> I currently have a desktop with a Zalman 600W PS, it was a pretty
>>> nice PS a few years ago when I got it, but now it looks like the
>>> system has been upgraded and grown again, and I'm starting to see
>>> signs that it's not producing enough power for the components anymore.

>> What signs are those exactly ?

> Well, we've discussed those on csiphs already, mainly the optical drives sending controller error messages even when
> they are not being used,

OK, I dont believe that those would be because you
are exceeding the 600W rating of the power supply.

I meant that the power supply may be failing, putting more noise
on the rails than is allowed. If thats the case, just replacing it with
another copy of the 600W supply should see that problem go away.

> and I'm also noticing some occasional spin retry errors on a few of my internal HDD's.

Thats unlikely to be because doesnt have enough current on the
12V rail even tho you do have quite a few hard drives from memory.

If that is the problem, it makes more sense ot replace some
of the smaller drives with new much larger ones than it does
to change the power supply, tho you should change the power
supply because of the optical drive symptoms you are getting
to see if thats due to the power supply.

You dont necessarily need such a big supply for that test tho.

>> That wouldnt normally be the case unless you have one hell of a video card in it.

> Well, the video card is not a monster of any kind, it's more upper mainstream, an AMD Radeon 6870.

Yeah, it only need 2 75W power connectors.

The 12V rails on that power supply are way above what it needs.

>>> So I'm looking at the market for bigger PS's, likely 750W+.

>>> When I got the Zalman, multi-rail +12V were the de riguer feature
>>> of the day. Now that I'm shopping for them again, I see that the
>>> manufacturers have done an about-face, and they are advertising the
>>> advantages of single-rail +12V. The old 600W had 4 rails at 16 Amps each.

>> And I would be amazed if you are exceeding that.

> Well, I ran my system components through a few power supply calculators:

I dont buy those. What matters is AMD's statement of what the video card needs,
http://www.amd.com/us/products/desktop/graphics/amd-radeon-hd-6000/hd-6870/pages/amd-radeon-hd-6870-overview.aspx#3
and thats where that 2 75W power connectors comes from,
and that detail you have already provided on 4 12V 16A rails.

Those are 192W rails, each one of them.

> http://extreme.outervision.com/PSUEngine said I needed 580W.
> http://www.thermaltake.outervision.com/Power said I needed 574W.
> http://support.asus.com/powersupply.aspx said I needed 900W!!!

Yeah, thats obviously silly.

> Obviously, the Asus rating is an outlier so I'm ignoring that one, but the other two seem to agree pretty close to
> each other,

But nothing like what you get when you calculate the 12V rails explicitly.

That power supply handles the video card fine with 2 of the rails
and you have two more for your hard drives which wont take
anything like 384W even if they are all trying to spin up at once.

> and that level is pretty close to the maximum power rating (within 96-97%) of my old PS.

Thats the problem with those power supply 'calculators', they
dont actually calculate what matters, the 12V rail currents.

And the 900W supply you are considering only has 1A more
12V current available anyway.

> And with the age of the PS advancing in years, its maximum
> capacity might actually be decreasing over time.

Nope, that doesnt happen.

What you can get is a deterioration of the low ESR caps and that
sees a lot more noise on the rails than there should be, but you dont
see a reduction in the rail current capacity and even if you did you
are nowhere near the maximum currents on any of those 12V rails.

> When I first obtained this 600W PS, the PS calculator showed that my system requirement was only in the upper 400W
> range.

Do you mean that the calculator has changed, or that
what you have in that system has changed that much ?

> So I thought I had more than enough leeway, but it looks like the various upgrades have quickly taken up most of that
> leeway since then.

Or the calculator has changed since then. What have you changed upgrade wise ?

>>> The new single rails I'm seeing seem to have a rail at anywhere from 45A to 65A!

>> And even the biggest is only 1A more than you currently have.

> When you add it up, yes the 4 separate rails come out to about 64A, but the point is is it possible that some of the
> rails are overloaded by themselves?

Nope, not with that particular video card.

> Would it be easier to distribute the power if there
> was a single larger rail rather than 4 smaller rails?

No, in fact its harder because you cant do a remote sense
so that the highest current rail is seeing 12V at the pins
without increasing what the other connects get at the pins.

Not that that matter much, the specs on the variation in the 12V rails is pretty wide.

And you have the other problem with a single rail too, limiting the
current to say 75A can still see a decent fire with some shorts.

You dont get that with 4 seperate 16A max current rails. 200W
isnt that bad as long as there is someone around to turn it off.

800W can be pretty spectacular in the very small space of a
single molex nylon connector.

>>> Why have the manufacturers done the about-face on single-rail vs. multi-rail?

>> So they dont have to have 4 separate 12V regulators.

> I found one possible explanation here:

> http://www.overclock.net/t/88626/info-do-you-need-multiple-12v-rails

> According to the above, the EU had mandated that no single +12V rail could exceed 20A, and that later Intel also
> embraced that EU rule, and further reduced that down to 18A. But now it looks like Intel no longer requires the 18A
> rule.

Yeah, if thats accurate, it likely is the reason for the change.

> I'm not sure if the EU has also dropped its 20A requirement, but here in North America there is no longer a need to
> have separate rails anymore, so we can go to single super-rails.

I dont like the idea of a single rail that can in theory deliver 800W
being able to do short circuit protection adequately myself.

Corse most of the time a short would just blow off quite literally but that doesnt always happen.

[Rod Speed]

Grant wrote

But its got real downsides short protection and fire prevention wise.

An 800W short can be quite spectacular.

[Yousuf Khan]

On 21/03/2012 8:28 PM, Grant wrote:
> Multi-rail was a cheap way to produce the high power, but it limits
> the distribution of that power into defined loads, loads that the user
> would perhaps not be able to judge correctly.
>
> Single rail makes distributing the 12V a 'don't care' as far as splitting
> up the load to suit the power supply. Much simpler, more efficient.
>
> Grant.

That's sort of what I am thinking too. I'm thinking that even if 600W is
sufficient for powering my entire system, that certain rails might be
underpowered depending on what's attached to them. Without a block
diagram of my PS, I have no way of knowing which cables go to which
rails. The single-rail design will remove all of that guess-work.

I think I also noticed that these new PS's are now designated for North
America or Europe, etc. So I think the manufacturers might be tailoring
their PS'es to avoid regulatory traps where there are some. The EU's
regulations were no doubt geared towards safety concerns several years
ago, but perhaps with the advance in technology, having a huge current
flowing through a single rail might not be as dangerous as it was in the
past.

Yousuf Khan

[Yousuf Khan]

On 21/03/2012 10:38 PM, Paul wrote:
> The HD6870 is 124 to 147 watts. One of the cards quoted here could be
> an overclock. Try doing your power calculation manually.
>
> http://www.xbitlabs.com/articles/graphics/display/asus-eah6870-directcu_4.html#sect0

No, mine is a Sapphire 6870, which might be pretty close to a reference
design.

Yousuf Khan

[Yousuf Khan]

On 21/03/2012 11:51 PM, Rod Speed wrote:
> Yousuf Khan wrote

>> Well, we've discussed those on csiphs already, mainly the optical drives sending controller error messages even when
>> they are not being used,
>
> OK, I dont believe that those would be because you
> are exceeding the 600W rating of the power supply.

Maybe not the overall power supply rating, but maybe some of the
individual rails might be undercharged.

> I meant that the power supply may be failing, putting more noise
> on the rails than is allowed. If thats the case, just replacing it with
> another copy of the 600W supply should see that problem go away.
>
>> and I'm also noticing some occasional spin retry errors on a few of my internal HDD's.
>
> Thats unlikely to be because doesnt have enough current on the
> 12V rail even tho you do have quite a few hard drives from memory.

Well, I do have six internal hard drives right now, and one optical
drive (Blu-Ray burner). It's the number of error messages that I'm
seeing on the BR burner that's got me most worried, but also recently I
saw a worrying pop-up message from Hard Disk Sentinel that it is
predicting an imminent failure of my boot drive too. I don't know which
of the rails all of these drives are connected to, but if they are all
connected to the same rail (very likely) then they might be all sharing
current from a diminished resource. I wonder how much current each of
the optical and hard drives use?

>>> That wouldnt normally be the case unless you have one hell of a video card in it.
>
>> Well, the video card is not a monster of any kind, it's more upper mainstream, an AMD Radeon 6870.
>
> Yeah, it only need 2 75W power connectors.
>
> The 12V rails on that power supply are way above what it needs.

One or two rails would go to the motherboard, another one would go to
the video card, and the last rail would be left for all of the rest of
the peripherals. I've mostly had no problems with motherboard components
(CPU, RAM, PCI cards), no problems with the video card, but the rest of
the system is all supplied by one rail, such as drives and fans and
lights. I won't really notice any power problems with the fans or
lights, but the drives might be pretty sensitive.

> That power supply handles the video card fine with 2 of the rails
> and you have two more for your hard drives which wont take
> anything like 384W even if they are all trying to spin up at once.

I don't think the video card gets two whole rails to itself. The
motherboard 24-pin connector is one rail which would power the PCI/PCI-e
slots, chipset and RAM; and maybe it'll feed a few Watts to the CPU too.
Then another 6-pin plug would be a rail for the CPU alone, which also
plugs into the motherboard. Then a couple of video power connectors
would go into the video card, which would likely come from one rail by
itself. The video card would also receive some power from the
motherboard through the PCI-e slot. So the video card might have at most
maybe 1.5 rails for its use (partial motherboard rail & full video
rail). And the last rail for everything else in the system.

>> and that level is pretty close to the maximum power rating (within 96-97%) of my old PS.
>
> Thats the problem with those power supply 'calculators', they
> dont actually calculate what matters, the 12V rail currents.
>
> And the 900W supply you are considering only has 1A more
> 12V current available anyway.

Well, I'm not really considering a 900W PS, more likely a 750W one.

>> When I first obtained this 600W PS, the PS calculator showed that my system requirement was only in the upper 400W
>> range.
>
> Do you mean that the calculator has changed, or that
> what you have in that system has changed that much ?

Yup, the stuff in the system has changed that much. This system is in a
constant state of evolution, including the case itself. I upgraded from
a mid-tower with a capacity for only four 3.5" drives to one with six
3.5" drives, and then it quickly evolved to to fill up those additional
drive slots. Also there was a video card upgrade, and a CPU upgrade
along the way too.

>> When you add it up, yes the 4 separate rails come out to about 64A, but the point is is it possible that some of the
>> rails are overloaded by themselves?
>
> Nope, not with that particular video card.

I don't think the video card is the issue here at all! Just those drives
in combination with all of the other powered peripherals inside that
system. I played around with the figures in one of the PS calculators,
and I found out that it's assuming 13W per 7200-rpm SATA hard drive, 24W
per 7200-rpm IDE HDD, 29W per Blu-Ray burner, 34W per DVD burner.

Based on that I currently have 129W in internal drives alone (4 SATA
HDD, 2 IDE HDD, 1 BR). When I previously had the dual DVD burners rather
than the single Blu-Ray, I had 168W worth of drives! This is now
starting to explain why my two DVD burners failed simultaneously.

I also have 4x 250mm case fans on the system (they came with the new
case). Each is regular fan is rated at 12W, and each LED fan is 13W.
Based on that I have 49W worth of fans (3 regular, 1 LED). Adding to the
previous figures of 129W and 168W brings them to overall totals of 178W
and 217W, respectively! If I only have 192W to play with per rail, then
I was well over when I had two DVD burners, and I'm sitting on the edge
still now.

>> Would it be easier to distribute the power if there
>> was a single larger rail rather than 4 smaller rails?
>
> No, in fact its harder because you cant do a remote sense
> so that the highest current rail is seeing 12V at the pins
> without increasing what the other connects get at the pins.
>
> Not that that matter much, the specs on the variation in the 12V rails is pretty wide.
>
> And you have the other problem with a single rail too, limiting the
> current to say 75A can still see a decent fire with some shorts.

That is obviously a worry, and that's why they didn't do this in the
past. I'm hoping that now that they are doing it, that they may have
found a way to keep it under control these days?

Yousuf Khan

[Rod Speed]

Yousuf Khan wrote

> Grant wrote

>> Multi-rail was a cheap way to produce the high power, but it limits the distribution of that power into defined
>> loads, loads that the user would perhaps not be able to judge correctly.

>> Single rail makes distributing the 12V a 'don't care' as far as splitting up the load to suit the power supply. Much
>> simpler, more efficient.

> That's sort of what I am thinking too.

Thats radically overstated.

> I'm thinking that even if 600W is sufficient for powering my entire system, that certain rails might be underpowered
> depending on what's attached to them.

Nope, its easy to calculate that they arent.

> Without a block diagram of my PS, I have no way of knowing which cables go to which rails.

Its likely obvious from the power supply specs.

And if it isnt, you can just open the power supply and
see which of the connector leads are soldered together
and so see which connectors are on which rails.

Not worth bothering to do it tho, even if the two power connectors
the video card uses are on the one rail, that will still not exceed the rail
rating of 192W given that the video card needs 2 75W 12V connectors.
Thats only 150W, well within what any single rail can supply.

And you know it can supply them anyway because the video card works fine.

> The single-rail design will remove all of that guess-work.

There is no guess work.

> I think I also noticed that these new PS's are now designated for
> North America or Europe, etc. So I think the manufacturers might be
> tailoring their PS'es to avoid regulatory traps where there are some.

Unlikely if they both have a single 12V rail.

> The EU's regulations were no doubt geared towards safety concerns several years ago,

Yes, and it should be easy to check if that requirement has changed.

> but perhaps with the advance in technology, having
> a huge current flowing through a single rail might not be as dangerous as it was in the past.

Thats not right. The danger is with a short on that rail and
nothing has changed on that in that time technology wise.

That rail still has to have the most vulnerable molex connectors on it even now.

[Rod Speed]

Yousuf Khan wrote

Most Sapphires arent, actually.

Its all completely academic, you know that video card works fine on that particular power supply.

Even if it is loading down one of the 12V rails too much,
that wont be the rail that used for the optical drives.

[Rod Speed]

Yousuf Khan wrote

> Rod Speed wrote
>> Yousuf Khan wrote

>>> Well, we've discussed those on csiphs already, mainly the optical drives sending controller error messages even when
>>> they are not being used,

>> OK, I dont believe that those would be because you
>> are exceeding the 600W rating of the power supply.

> Maybe not the overall power supply rating, but maybe some of the individual rails might be undercharged.

You mean overloaded.

No, that isnt possible. The video card needs 2 75W supplys.

Even if they are both supplied from a single 12V rail in that supply,
thats only 150W from a rail that can deliver 192W, so there is bags
of margin in hand and you know the video card works fine anyway.

You cant possibly be exceeding what the other rails can deliver,
even 10 hard drives wouldnt do that if they are all starting at once,
and the symptoms you see arent when the drives are starting up
anyway with the optical drive symptoms.

>> I meant that the power supply may be failing, putting more noise
>> on the rails than is allowed. If thats the case, just replacing it with another copy of the 600W supply should see
>> that problem go away.

>>> and I'm also noticing some occasional spin retry errors on a few of
>>> my internal HDD's.

>> Thats unlikely to be because doesnt have enough current on the
>> 12V rail even tho you do have quite a few hard drives from memory.

> Well, I do have six internal hard drives right now, and one optical drive (Blu-Ray burner).

Thats fine even if they are all on a single 192W 16A rail.

And you dont see the optical drive symptom at hard drive spinup time anyway.

> It's the number of error messages that I'm seeing on the BR burner that's got me most worried,

Yes, and they wont be happening when all those drives are spinning
up. Thats the only time that those drives will be taking a lot of current.

> but also recently I saw a worrying pop-up message from Hard Disk Sentinel that it is predicting an imminent failure of
> my boot drive too.

Its notorious for crying wolf.

> I don't know which of the rails all of these drives are connected to, but if they are all connected to the same rail
> (very likely) then they might be all sharing current from a diminished resource.

I doubt it. I bet that if you do total the startup currents for all those
drives which you havent specified, they wont exceed the surge rating
of one of the rails. And even if they do, the most that you might see
is a few slow starts with the worst of the drives which might be what
HDS is mindlessly screaming about.

> I wonder how much current each of the optical and hard drives use?

Its in the datasheets for all of them. You want the startup current.

You dont need to worry with the optical drive, it will be
be peanuts compared with the total of the hard drives.

>>>> That wouldnt normally be the case unless you have one hell of a video card in it.

>>> Well, the video card is not a monster of any kind, it's more upper mainstream, an AMD Radeon 6870.

>> Yeah, it only need 2 75W power connectors.

>> The 12V rails on that power supply are way above what it needs.

> One or two rails would go to the motherboard, another one would go to the video card,

Those rails can supply all the video card needs fine.

The video card needs 150W and each rail can deliver 192W

> and the last rail would be left for all of the rest of the peripherals.

Likely. But thats still plenty.

> I've mostly had no problems with motherboard components (CPU, RAM, PCI cards), no problems with the video card,

So it must be getting the power it needs.

> but the rest of the system is all supplied by one rail, such as drives and fans and lights.

Yes, but even if that rail is a bit overloaded when the hard
drives are all spinning up at once, the worst that can do is
see the spinup time a bit longer than it would otherwise be
with just one drive connected.

They clearly do spin up.

> I won't really notice any power problems with the fans or lights, but the drives might be pretty sensitive.

Nope, they arent at spinnup time and thats the only
time they are likely to be overloading even one rail.

>> That power supply handles the video card fine with 2 of the rails
>> and you have two more for your hard drives which wont take
>> anything like 384W even if they are all trying to spin up at once.

> I don't think the video card gets two whole rails to itself.

The video card datasheet does say it has two power connectors.

> The motherboard 24-pin connector is one rail which would power the PCI/PCI-e slots, chipset and RAM; and maybe it'll
> feed a few Watts to the CPU too. Then another 6-pin plug would be a rail for the CPU alone, which also plugs into the
> motherboard.

And clearly that works fine.

> Then a couple of video power connectors would go into the video card, which would likely come from one rail by itself.
> The video card would also receive some power from the motherboard through the PCI-e slot. So the video card might have
> at most maybe 1.5 rails for its use (partial motherboard rail & full video rail).

And it works fine so it must be getting what it needs 12V wise.

> And the last rail for everything else in the system.

You dont kinow that with the fans etc particularly.

Yes, the hard drives may well be on one rail, but that should
be fine too and the worst you might see is some of the drives
being a bit slow to spin up, a complete yawn basically.

It wont be whats producing the symptoms with the optical drive
because the hard drives will have spun up long before you ever
write anything with the optical drive and so the current draw of
the hard drives will be well down on the startup currents.

>>> and that level is pretty close to the maximum power rating (within 96-97%) of my old PS.

>> Thats the problem with those power supply 'calculators', they
>> dont actually calculate what matters, the 12V rail currents.

>> And the 900W supply you are considering only has 1A more
>> 12V current available anyway.

> Well, I'm not really considering a 900W PS, more likely a 750W one.

So you may not end up with any more 12V current at all.

>>> When I first obtained this 600W PS, the PS calculator showed that my system requirement was only in the upper 400W
>>> range.

>> Do you mean that the calculator has changed, or that
>> what you have in that system has changed that much ?

> Yup, the stuff in the system has changed that much. This system is in a constant state of evolution, including the
> case itself. I upgraded
> from a mid-tower with a capacity for only four 3.5" drives to one with six 3.5" drives, and then it quickly evolved to
> to fill up those additional drive slots. Also there was a video card upgrade, and a
> CPU upgrade along the way too.

I've never believed those calculators, I calculate the actual rail currents.

>>> When you add it up, yes the 4 separate rails come
>> out to about 64A, but the point is is it possible that some of the rails are overloaded by themselves?

>> Nope, not with that particular video card.

> I don't think the video card is the issue here at all! Just those
> drives in combination with all of the other powered peripherals
> inside that system.

They arent all necessarily on just one rail and their currents arent
significant anyway compared with the hard drive startup currents.

> I played around with the figures in one of the PS calculators, and I found out that it's assuming 13W per 7200-rpm
> SATA
> hard drive, 24W per 7200-rpm IDE HDD,

Thats pretty bogus when what matters is the startup currents.

> 29W per Blu-Ray burner, 34W per DVD burner.

Its silly to assume that all blue ray and dvd burners will consume
the same amount within 1W

> Based on that I currently have 129W in internal drives alone (4 SATA HDD, 2 IDE HDD, 1 BR).

And one rail can deliver 192W, bags of margin.

> When I previously had the dual DVD burners rather than the single Blu-Ray, I had 168W worth of drives!

Still fine for a 192W rail.

> This is now starting to explain why my two DVD burners failed simultaneously.

Nope. Even if the rail was overloaded, and it isnt,
that wont kill two DVD burners simultaneously.

> I also have 4x 250mm case fans on the system (they came with the new case). Each is regular fan is rated at 12W, and
> each LED fan is 13W. Based on that I have 49W worth of fans (3 regular, 1 LED). Adding to the previous figures of 129W
> and 168W brings them to overall totals of 178W and 217W, respectively!

Yebbut the hard drives numbers are bogus.

> If I only have 192W to play with per rail, then I was well over when I had two DVD burners, and I'm sitting on the
> edge still now.

Nope, because the worst that might happen is that a couple of the
hard drives might spin up a little more slowly than they would if they
were the only drive in the system and thats a complete yawn in practice.

>>> Would it be easier to distribute the power if there
>>> was a single larger rail rather than 4 smaller rails?

>> No, in fact its harder because you cant do a remote sense
>> so that the highest current rail is seeing 12V at the pins
>> without increasing what the other connects get at the pins.

>> Not that that matter much, the specs on the variation in the 12V rails is pretty wide.

>> And you have the other problem with a single rail too, limiting the
>> current to say 75A can still see a decent fire with some shorts.

> That is obviously a worry, and that's why they didn't do this in the past. I'm hoping that now that they are doing it,
> that they may have found a way to keep it under control these days?

Nope, it isnt even possible. 75A is one hell of a current at DC.

[Rod Speed]

KR wrote

> Yousuf Khan <bbb...@spammenot.yahoo.com> wrote

>> I currently have a desktop with a Zalman 600W PS, it was a pretty
>> nice PS a few years ago when I got it, but now it looks like the
>> system has been upgraded and grown again, and I'm starting to see
>> signs that it's not producing enough power for the components
>> anymore. So I'm looking at the market for bigger PS's, likely 750W+.

>> When I got the Zalman, multi-rail +12V were the de riguer feature
>> of the day. Now that I'm shopping for them again, I see that the
>> manufacturers have done an about-face, and they are advertising the
>> advantages of single-rail +12V. The old 600W had 4 rails at 16 Amps
>> each. The new single rails I'm seeing seem to have a rail at
>> anywhere from 45A to 65A! Why have the manufacturers done the
>> about-face on single-rail vs. multi-rail?

> Traditionally it was always considered good practice to separate the power
> for digital and analog circuits as much as possible to prevent interference.
> This would especially be the case in audio systems.

> In the case of a PC, this would mean keeping the supply for motors
> (such as Hard Drives, CD ROMS etc on a separate circuit, so as to
> minimise any electrical noise from these from interfering with digital
> circuits - assuming this really is a problem in a modern PC.

Thats why there are separate 5V, 3.3V and 12V rails.

> Usually having separate supply cables from a common power source is sufficient.

> I would suggest it is more likely done to keep the
> currents manageable on particular circuits however.

Particularly when there are separate rails at the same voltage.

> You might have 60A available, but in cases like this
> where one circuit is never going to need more than
> (say) 15a, it is safer to split it into 4 separate circuits.

Doesnt explain why they have now reverted to a single 12V rail.

> Exactly the same is done in your home fusebox in having
> separate fuses and circuits for your lights, power points,
> air con, water heater, stove etc, rather than just having
> a single 200A fuse for the entire lot.

The british do in fact have a single ring main for most of the GPOs.

That for other reasons tho, particularly minimising the wire guage used
and making the system more tolerant of poor connections at the GPOs etc.

[PeterC]

On Wed, 21 Mar 2012 18:30:38 -0400, Paul wrote:

<snip very useful information>

> The keyword "SELV" comes
> to mind, but that's about all I remember now.

"SELV" means, IIRC, "Safe Extra-Low Voltage", often used for light fittings
in bathrooms etc.
Bear in mind that "LV", to a mains engineer, means <1000V!
--
Peter.
The gods will stay away
whilst religions hold sway

[Grant]

Yes? Just how does a short circuit dissipate 800W?

Grant.

[Yousuf Khan]

On 22/03/2012 2:47 AM, Rod Speed wrote:
> Yousuf Khan wrote

>> Rod Speed wrote

>>> And the 900W supply you are considering only has 1A more
>>> 12V current available anyway.
>
>> Well, I'm not really considering a 900W PS, more likely a 750W one.
>
> So you may not end up with any more 12V current at all.

Unless it's a single-rail, then it'll have a *lot* more 12V current.
I've been window-shopping, most of the latest high-end PS'es are now all
single-rail, very few multi-rail left anymore.

>> I played around with the figures in one of the PS calculators, and I found out that it's assuming 13W per 7200-rpm
>> SATA
>> hard drive, 24W per 7200-rpm IDE HDD,
>
> Thats pretty bogus when what matters is the startup currents.

Well, that's likely what they are assuming, the worst-case scenarios,
which is usually startup currents.

>> 29W per Blu-Ray burner, 34W per DVD burner.
>
> Its silly to assume that all blue ray and dvd burners will consume
> the same amount within 1W

It's probably just an average they are taking, or maybe a worst-case.

>> Based on that I currently have 129W in internal drives alone (4 SATA HDD, 2 IDE HDD, 1 BR).
>
> And one rail can deliver 192W, bags of margin.
>
>> When I previously had the dual DVD burners rather than the single Blu-Ray, I had 168W worth of drives!
>
> Still fine for a 192W rail.
>
>> This is now starting to explain why my two DVD burners failed simultaneously.
>
> Nope. Even if the rail was overloaded, and it isnt,
> that wont kill two DVD burners simultaneously.

But the fact remains that they *did* die simultaneously, so if this is
not the most likely reason for it, then I invite you to come up with
another reason.

>> I also have 4x 250mm case fans on the system (they came with the new case). Each is regular fan is rated at 12W, and
>> each LED fan is 13W. Based on that I have 49W worth of fans (3 regular, 1 LED). Adding to the previous figures of 129W
>> and 168W brings them to overall totals of 178W and 217W, respectively!
>
> Yebbut the hard drives numbers are bogus.

Again, I'm just working with the online PS calculator figures here, I
have no reason to doubt them. So again, if you got better numbers, I
invite you to present them, and why.

>> If I only have 192W to play with per rail, then I was well over when I had two DVD burners, and I'm sitting on the
>> edge still now.
>
> Nope, because the worst that might happen is that a couple of the
> hard drives might spin up a little more slowly than they would if they
> were the only drive in the system and thats a complete yawn in practice.

Which is basically the problem that's happening with most of the hard
drives, but it still counts against the drive as a SMART error in the
logs regardless. There's no way to tell if a spin retry error is due to
power supply problems or due to actual mechanical stiction. But
PS-generated spin retry is easy to fix, and I'd rather leave the spin
retry errors to detect actual mechanical stiction rather than these
bogus power problems. Mechanical stiction will tell me that it's really
time to replace the drives.

As for the optical drive(s), the errors don't crop up during startup,
they show up in the Windows Event logs randomly. That means that they
occur when the system is already up and running and in a steady state or
even idle. As mentioned, the optical drives are empty most of the time,
so why they are sending out error messages when there is nothing in them
is beyond me. I can only assume Windows periodically polls the status of
these optical drives, and that's when we see these error messages.

Yousuf Khan

[Loren Pechtel]

On Wed, 21 Mar 2012 19:45:30 -0400, Yousuf Khan
<bbb...@spammenot.yahoo.com> wrote:

>Well, I ran my system components through a few power supply calculators:
>
>http://extreme.outervision.com/PSUEngine said I needed 580W.
>http://www.thermaltake.outervision.com/Power said I needed 574W.
>http://support.asus.com/powersupply.aspx said I needed 900W!!!
>
>Obviously, the Asus rating is an outlier so I'm ignoring that one, but
>the other two seem to agree pretty close to each other, and that level
>is pretty close to the maximum power rating (within 96-97%) of my old
>PS. And with the age of the PS advancing in years, its maximum capacity
>might actually be decreasing over time.

I would get a Kill-A-Watt and see what it's really using.

I haven't checked mine when the needles are pegged but at normal
desktop usage I was surprised at how little my UPS says it's
delivering.

[Rod Speed]

Grant wrote

Where do you believe that the 800W ends up ?

Its got to end up somewhere.

[Rod Speed]

Yousuf Khan wrote
> Rod Speed wrote
>> Yousuf Khan wrote
>>> Rod Speed wrote

>>> I played around with the figures in one of the PS calculators, and I found out that it's assuming 13W per 7200-rpm
>>> SATA
>>> hard drive, 24W per 7200-rpm IDE HDD,

>> Thats pretty bogus when what matters is the startup currents.

> Well, that's likely what they are assuming, the worst-case scenarios,

Nope. There is no 2:1 ratio between the startup currents with SATA
and IDE HDDs, most obviously with the drives available in both formats.

> which is usually startup currents.

>>> 29W per Blu-Ray burner, 34W per DVD burner.

>> Its silly to assume that all blue ray and dvd burners will consume the same amount within 1W

> It's probably just an average they are taking, or maybe a worst-case.

It isnt even an average with that silly 1W precision,
its straight from someone's arse.

>>> Based on that I currently have 129W in internal drives alone (4 SATA HDD, 2 IDE HDD, 1 BR).

>> And one rail can deliver 192W, bags of margin.

>>> When I previously had the dual DVD burners rather than the single Blu-Ray, I had 168W worth of drives!

>> Still fine for a 192W rail.

>>> This is now starting to explain why my two DVD burners failed simultaneously.

>> Nope. Even if the rail was overloaded, and it isnt,
>> that wont kill two DVD burners simultaneously.

> But the fact remains that they *did* die simultaneously,

Yes, but it cant have been due to that rail being overloaded
with all the hard drives spiinning up at once, because the most
that will do is see the 12V rail sag a bit for the short time that the
hard drives are taking the maximum startup current, and a small
sag in the 12V wont be what killed both drives simultaneously.

> so if this is not the most likely reason for it,

It isnt.

> then I invite you to come up with another reason.

Dont have to, it cant be that.

Bet if you actually put a decent max min multimeter on the rail,
you wont find it sags much at all.

>>> I also have 4x 250mm case fans on the system (they came with the new case). Each is regular fan is rated at 12W, and
>>> each LED fan is 13W. Based on that I have 49W worth of fans (3 regular, 1 LED). Adding to the previous figures of
>>> 129W and 168W brings them to overall totals of 178W and 217W, respectively!

>> Yebbut the hard drives numbers are bogus.

> Again, I'm just working with the online PS calculator figures here,

And that is where you are going wrong. You have to use the real
startup current numbers from the hard drive datasheets instead.

> I have no reason to doubt them.

You have every reason to doubt them on that terminal
stupidity of a 2:1 ratio between sata and ide drives
when the same drive is available in both formats alone.

And you cant just add the DVD and blue ray numbers
to the hard drive numbers either, because the hard drive
spinup currents dont happen at the same time that the
burners are presenting their maximum load to the 12V rails.

> So again, if you got better numbers,

I already told you where to get them, from the
hard drive datasheets, the spinup currents.

> I invite you to present them,

Cant do that, you never specified the hard drive model numbers.

Everest will give them to you without even opening the case.

> and why.

I already told you why, repeatedly.

>>> If I only have 192W to play with per rail, then I was well over
>>> when I had two DVD burners, and I'm sitting on the edge still now.

>> Nope, because the worst that might happen is that a couple of the
>> hard drives might spin up a little more slowly than they would if they were the only drive in the system and thats a
>> complete yawn in practice.

> Which is basically the problem that's happening with most of the hard drives,

I dont believe that with that most claim.

> but it still counts against the drive as a SMART error in the logs regardless.

Nope. Its just REPORTING the longer spin up time, it isnt counting against anything.

> There's no way to tell if a spin retry error is due to power supply problems or due to actual mechanical stiction.

Corse there is, you run it with just a couple of drives for a test.

> But PS-generated spin retry is easy to fix, and I'd rather leave the spin retry errors to detect actual mechanical
> stiction

You dont get enough mechanical stiction now to matter because
modern drives unload the heads from the media at shutdown now.

> rather than these bogus power problems. Mechanical stiction will tell me that it's really time to replace the drives.

If you see mechanical stiction, the drive wont spin up at all.

> As for the optical drive(s), the errors don't crop up during startup, they show up in the Windows Event logs randomly.

So they cant be due to the rail not being adequate.

> That means that they occur when the system is already up and running and in a steady state or even idle.

So they cant be due to the rail not being adequate.

> As mentioned, the optical drives are empty most of the time, so why they are sending out error messages when there is
> nothing in them is beyond me.

One obvious possibility, is, as I said, that the
power supply has too much noise on the 5V rail.

The only real way to check that possibility if you dont have
a CRO etc and dont know how to use one is to replace the
power supply and see if the problem goes away.

And you dont need anything special power supply wise for that
test, you can see if the problem goes away with a normal power
supply by leaving most of the hard drives unplugged for the test.

> I can only assume Windows periodically polls the status of these optical drives, and that's when we see these error
> messages.

Even if it does, it cant be because the rail is overloaded,
because the hard drives arent spinning up at that time.

[Rod Speed]

Loren Pechtel wrote

> Yousuf Khan <bbb...@spammenot.yahoo.com> wrote

>> Well, I ran my system components through a few power supply calculators:

>> http://extreme.outervision.com/PSUEngine said I needed 580W.
>> http://www.thermaltake.outervision.com/Power said I needed 574W.
>> http://support.asus.com/powersupply.aspx said I needed 900W!!!

>> Obviously, the Asus rating is an outlier so I'm ignoring that one,
>> but the other two seem to agree pretty close to each other, and that
>> level is pretty close to the maximum power rating (within 96-97%) of
>> my old PS. And with the age of the PS advancing in years, its
>> maximum capacity might actually be decreasing over time.

> I would get a Kill-A-Watt and see what it's really using.

That doesnt tell you if a particular rail is getting overloaded.

You need a multimeter on the individual rails to check that.

> I haven't checked mine when the needles are pegged but at normal
> desktop usage I was surprised at how little my UPS says it's delivering.

Thats normal.

[Yousuf Khan]

On 22/03/2012 3:29 PM, Loren Pechtel wrote:
> I would get a Kill-A-Watt and see what it's really using.

I actually did get one at one time, but it turned out to be bad, so I
returned it, and I never bothered again.

Yousuf Khan

[Charlie]

>
> As for the optical drive(s), the errors don't crop up during startup,
> they show up in the Windows Event logs randomly.

I had the same thing and cured it by raising the CPU voltage slightly.

Charlie

[Grant]

On Fri, 23 Mar 2012 06:55:14 +1100, "Rod Speed" <rod.sp...@gmail.com> wrote:

>Grant wrote
>> Rod Speed <rod.sp...@gmail.com> wrote
>>> Grant wrote

...

>>>> Single rail makes distributing the 12V a 'don't care' as far as splitting
>>>> up the load to suit the power supply. Much simpler, more efficient.
>
>>> But its got real downsides short protection and fire prevention wise.
>
>>> An 800W short can be quite spectacular.
>
>> Yes? Just how does a short circuit dissipate 800W?
>
>Where do you believe that the 800W ends up ?

What has one's beliefs got to do with this?

>
>Its got to end up somewhere.

Not in the short circuit, no voltage, and since P(Watts) equals V(olts) * I(Amps)
there's no power in a short circuit ;)

Grant.

[Rod Speed]

Grant wrote
> Rod Speed <rod.sp...@gmail.com> wrote
>> Grant wrote
>>> Rod Speed <rod.sp...@gmail.com> wrote
>>>> Grant wrote

>>>>> Single rail makes distributing the 12V a 'don't care'
>>>>> as far as splitting up the load to suit the power supply.
>>>>> Much simpler, more efficient.

>>>> But its got real downsides short protection and fire prevention wise.

>>>> An 800W short can be quite spectacular.

>>> Yes? Just how does a short circuit dissipate 800W?

>> Where do you believe that the 800W ends up ?

> What has one's beliefs got to do with this?

Everything to do with your question.

>> Its got to end up somewhere.

> Not in the short circuit, no voltage,

There is still a voltage while the power supply is delivering
the full current that rail can supply with a single rail.

> and since P(Watts) equals V(olts) * I(Amps) there's no power in a short circuit ;)

Thanks for that completely superfluous proof that you dont have a fucking clue.

[Yousuf Khan]

Were you overclocking? I'm not overclocking, at the moment.

Yousuf Khan

[Loren Pechtel]

Ours gets dragged out on occasion. It's convinced my wife that she
was wrong about the cost of various things.

[a1pcfixer]

Rod,

> > and since P(Watts) equals V(olts) * I(Amps) there's no power in a short circuit ;)
>
> Thanks for that completely superfluous proof that you dont have a fucking clue.

Lol~!!!!

[Arno]

In comp.sys.ibm.pc.hardware.storage Yousuf Khan <bbb...@spammenot.yahoo.com> wrote:
> I currently have a desktop with a Zalman 600W PS, it was a pretty nice
> PS a few years ago when I got it, but now it looks like the system has
> been upgraded and grown again, and I'm starting to see signs that it's
> not producing enough power for the components anymore. So I'm looking at
> the market for bigger PS's, likely 750W+.

> When I got the Zalman, multi-rail +12V were the de riguer feature of the
> day. Now that I'm shopping for them again, I see that the manufacturers
> have done an about-face, and they are advertising the advantages of
> single-rail +12V. The old 600W had 4 rails at 16 Amps each. The new
> single rails I'm seeing seem to have a rail at anywhere from 45A to 65A!
> Why have the manufacturers done the about-face on single-rail vs.
> multi-rail?

I suspect marketing. The onld ones were not really muti-rail
either, more like "multi-rectifier". For proper multi-rail
you have to have a regulator, power switches, rectifier and
power-transformer for each rail.

It is also possible that recitifers have gotten better.

Arno
--
Arno Wagner, Dr. sc. techn., Dipl. Inform., CISSP -- Email: ar...@wagner.name
GnuPG: ID: 1E25338F FP: 0C30 5782 9D93 F785 E79C 0296 797F 6B50 1E25 338F
----
Cuddly UI's are the manifestation of wishful thinking. -- Dylan Evans

[Arno]

Yousuf Khan <bbb...@spammenot.yahoo.com> wrote:
> On 21/03/2012 8:28 PM, Grant wrote:
>> Multi-rail was a cheap way to produce the high power, but it limits
>> the distribution of that power into defined loads, loads that the user
>> would perhaps not be able to judge correctly.
>>
>> Single rail makes distributing the 12V a 'don't care' as far as splitting
>> up the load to suit the power supply. Much simpler, more efficient.
>>
>> Grant.

> That's sort of what I am thinking too. I'm thinking that even if 600W is
> sufficient for powering my entire system, that certain rails might be
> underpowered depending on what's attached to them. Without a block
> diagram of my PS, I have no way of knowing which cables go to which
> rails. The single-rail design will remove all of that guess-work.

You may also have a different problem, as 600W is really a lot.
For example you may have filter capactiros on the mains side or the
outputs siede that have lost a lot of their capacity.

What symptoms are you observing?

> I think I also noticed that these new PS's are now designated for North
> America or Europe, etc. So I think the manufacturers might be tailoring
> their PS'es to avoid regulatory traps where there are some. The EU's
> regulations were no doubt geared towards safety concerns several years
> ago, but perhaps with the advance in technology, having a huge current
> flowing through a single rail might not be as dangerous as it was in the
> past.

I have not noticed that trend. For example Seasonic just
has the same model for the whole world. I also don't think
inrush-current should be that miuch of a problem with
regard to electrical safety, unless you have really flimsy
installations. For example, here it is 10A rated at 235V, with
the fuses having a 5000A switch-off rating (maximum current they
can reliably interrupt before arcing starts due to plasma
generation). Wireing is 1.5mm^2 copper that can take up
to a few hundreds of A for brief periods of time.
I doubt the mains-side capacitors typically used can
cause trouble for that.

Arno

> Yousuf Khan

[Charlie]

No, but I had lowered the voltage to reduce the heat. Its an I7 CPU.
That didn't help much so I got a different heatsink which did help. When
I looked at the Event logs I noticed that the optical drive errors
started at about the time I lowered the voltage, so I raised the voltage
and haven't had an optical drive error since (about 1 year).

Charlie

[Arno]

Overclocking has about the same effect as lowering the voltage,
signals may not get quite enough time. Overclocking is worse though,
as things can overheat in addition.

Arno

[Yousuf Khan]

On 23/03/2012 11:56 AM, Charlie wrote:
> On 3/23/2012 12:39 AM, Yousuf Khan wrote:
>> Were you overclocking? I'm not overclocking, at the moment.
>

> No, but I had lowered the voltage to reduce the heat. Its an I7 CPU.
> That didn't help much so I got a different heatsink which did help. When
> I looked at the Event logs I noticed that the optical drive errors
> started at about the time I lowered the voltage, so I raised the voltage
> and haven't had an optical drive error since (about 1 year).

Well, then it seems like you put the CPU back to its recommended
settings. My CPU is already at its recommended settings.

Yousuf Khan

[Yousuf Khan]

On 23/03/2012 6:23 AM, Arno wrote:
> I suspect marketing. The onld ones were not really muti-rail
> either, more like "multi-rectifier". For proper multi-rail
> you have to have a regulator, power switches, rectifier and
> power-transformer for each rail.

Probably, but the effect was the same, namely that each of the 4 +12V
channels were limited in the amount of current they carried.

> It is also possible that recitifers have gotten better.

Yeah, it had better be, or else I should be smelling smoke quite quickly.

Yousuf Khan

[Paul]

The only way a rectifier gets better, is by disappearing.
In the picture here, the rectifier on the secondary is
replaced by a MOSFET.

("Synchronous rectification")

http://www.onsemi.com/pub_link/Collateral/AND8460-D.PDF

Paul

[Charlie]

I did not raise the voltage back to where it was. Just enough to stop
the errors. I'm not saying that your errors are caused by the same
thing as mine. Just giving you something else to try.

Charlie

[Yousuf Khan]

On 23/03/2012 9:10 PM, Paul wrote:
> Yousuf Khan wrote:
>> On 23/03/2012 6:23 AM, Arno wrote:
>>> It is also possible that recitifers have gotten better.
>>
>> Yeah, it had better be, or else I should be smelling smoke quite quickly.
>

> The only way a rectifier gets better, is by disappearing.
> In the picture here, the rectifier on the secondary is
> replaced by a MOSFET.
>
> ("Synchronous rectification")
>
> http://www.onsemi.com/pub_link/Collateral/AND8460-D.PDF

Interesting.

Yousuf Khan

[larry moe 'n curly]

Yousuf Khan wrote:
>
> I currently have a desktop with a Zalman 600W PS, it was a pretty
> nice PS a few years ago when I got it, but now it looks like the system
> has been upgraded and grown again, and I'm starting to see signs that
> it's not producing enough power for the components anymore.

> mainly the optical drives
> sending controller error messages even when they are not being used, and

> I'm also noticing some occasional spin retry errors on a few of my
> internal HDD's.

Bit-Tech.net says the 1GB Radeon 6870 uses from 128W - 247W. Power
estimators aren't very good and usually give numbers that are way too
high, and when XbitLabs.com took actual measurements, they got this
(associated article goes into much more detail):

www.xbitlabs.com/images/coolers/system-wattage/p40.png

Or you could plug your system into a Kill-A-Watt and multiply the watt
rating by about 80% to get the needed PSU wattage. BTW the maximum
capacity of a PSU varies with temperature, and many years ago PC Power
& Cooling said an Enermax rated for 550W @ 25C (room temperature)
dropped to 366W @ 40C (not much hotter than some case interiors) and
244W @ 50C.

If the drives are PATA instead of SATA, have you tried tightening the
power connectors from the PSU? The connectors are metal tubes, and
prying between them and their surrounding plastic can make them fit
more snugly.

I've had optical drives based on Philips designs (Acer/Benq/Aopen)
suddenly act up and make head seeking noises, even when empty. I
could never figure out what went wrong (reseated internal connectors,
resoldered power chips, tapped all over the circuit boards, tried
freeze spray), but if the drives were removed for a few months they'd
work again, for up to a year.

[Rod Speed]

larry moe 'n curly wrote

> Yousuf Khan wrote

>> I currently have a desktop with a Zalman 600W PS, it was a pretty
>> nice PS a few years ago when I got it, but now it looks like the
>> system has been upgraded and grown again, and I'm starting to see
>> signs that it's not producing enough power for the components anymore.

>> mainly the optical drives sending controller error messages
>> even when they are not being used, and I'm also noticing some
>> occasional spin retry errors on a few of my internal HDD's.

> Bit-Tech.net says the 1GB Radeon 6870 uses from 128W - 247W.

The datasheet says nothing like that.

> Power estimators aren't very good and usually give numbers that
> are way too high, and when XbitLabs.com took actual measurements,
> they got this (associated article goes into much more detail):

> www.xbitlabs.com/images/coolers/system-wattage/p40.png

And you dont have to measure with the 12V rail currents, they are in the datasheets.

> Or you could plug your system into a Kill-A-Watt and multiply
> the watt rating by about 80% to get the needed PSU wattage.

Makes a hell of a lot more sense to calculate the 12V rail currents using the datasheets.

And measure the system performance when you have a power supply
that you are wondering if its adequate using a decent max min multimeter,

> BTW the maximum capacity of a PSU varies with temperature,

Its normally determined by the currents that protection circuitry shut down at.

> and many years ago PC Power & Cooling said an Enermax rated
> for 550W @ 25C (room temperature) dropped to 366W @ 40C
> (not much hotter than some case interiors) and 244W @ 50C.

Dont believe those numbers.

> If the drives are PATA instead of SATA, have you tried
> tightening the power connectors from the PSU? The
> connectors are metal tubes, and prying between them and
> their surrounding plastic can make them fit more snugly.

Its better to release the contact from the shell and sqeeze the contact in a bit.

Or just try a different connector and see if the errors are seen with that one too.

In his case, because he has so many hard drives, it may even be the power Y adapters.

[Yousuf Khan]

On 23/03/2012 6:37 AM, Arno wrote:
> You may also have a different problem, as 600W is really a lot.
> For example you may have filter capactiros on the mains side or the
> outputs siede that have lost a lot of their capacity.
>
> What symptoms are you observing?

Well, I went through the power calculations elsewhere in the thread in a
response to Rod. Basically, the only problem I'm having is with storage
devices, both optical and hard drives. It's looking like all of the hard
drives, combined with optical drives, and fans and LED's is pushing the
current supply of one of the rails hard. The calculations showed that
it's using between 178W to 217W. The nominal power rating of the rail is
192W.

Yousuf Khan

[Arno]

In comp.sys.ibm.pc.hardware.storage Charlie <charl...@vereyezon.net> wrote:

In this case you will likely stikk have errors on occasion.
You need to raise it to where the errors apprarently stop, and
then a bit more. Of coruse if the errors are non-critical,
you do what you did. But you should be aware that this
can also cause other errors that may not be as visible.

[Arno]

Ah, so you have a _theoretical_ result indicating possible errors.
In that case you may want to redistribute your deicves a bit to
the other rails, not replace the PSU. But note that typically,
with a good quality PSU, 15% more load on one rail should not be
an issue, as long as it is not permanent load and the device is
overall not overloaded. You should also have had some overestimation
in that calculation if you did it right.

Arno

[Arno]

In comp.sys.ibm.pc.hardware.storage Paul <nos...@needed.com> wrote:
> Yousuf Khan wrote:
>> On 23/03/2012 6:23 AM, Arno wrote:
>>> I suspect marketing. The onld ones were not really muti-rail
>>> either, more like "multi-rectifier". For proper multi-rail
>>> you have to have a regulator, power switches, rectifier and
>>> power-transformer for each rail.
>>
>> Probably, but the effect was the same, namely that each of the 4 +12V
>> channels were limited in the amount of current they carried.
>>
>>> It is also possible that recitifers have gotten better.
>>
>> Yeah, it had better be, or else I should be smelling smoke quite quickly.
>>
>> Yousuf Khan

> The only way a rectifier gets better, is by disappearing.

No, definitely not. While syncronous rectifiers have their
merits, they are mostly for switchers without transformers,
as otherwise they drive cost up significantly. If you have
very low voltages (CPU, RAM), they are the only sensible
choice.

In PSUs with transformers, typically you use normal power
rectifiers, or shottky rectifiers. These have gotten slowly
better and cheaper.

[Arno]

In comp.sys.ibm.pc.hardware.storage Yousuf Khan <bbb...@spammenot.yahoo.com> wrote:

Standard concept, but too expensive with transformers.

[larry moe 'n curly]

Arno wrote:
>
> On 23/03/2012 9:10 PM, Paul wrote:
>
>> The only way a rectifier gets better, is by disappearing.
>> In the picture here, the rectifier on the secondary is
>> replaced by a MOSFET.
>>
>> ("Synchronous rectification")
>>
>> http://www.onsemi.com/pub_link/Collateral/AND8460-D.PDF
>

> Standard concept, but too expensive with transformers.

My only PSU with a MOSFET rectifier in it was so cheaply built that PC
Power & Cooling featured it in an ad as an example of a bad PSU.

[Charlie]

On 3/24/2012 9:11 AM, Arno wrote:
> In comp.sys.ibm.pc.hardware.storage Charlie<charl...@vereyezon.net> wrote:
>> On 3/23/2012 6:05 PM, Yousuf Khan wrote:
>>> On 23/03/2012 11:56 AM, Charlie wrote:
>>>> On 3/23/2012 12:39 AM, Yousuf Khan wrote:
>>>>> Were you overclocking? I'm not overclocking, at the moment.
>>>>
>>>> No, but I had lowered the voltage to reduce the heat. Its an I7 CPU.
>>>> That didn't help much so I got a different heatsink which did help. When
>>>> I looked at the Event logs I noticed that the optical drive errors
>>>> started at about the time I lowered the voltage, so I raised the voltage
>>>> and haven't had an optical drive error since (about 1 year).
>>>
>>> Well, then it seems like you put the CPU back to its recommended
>>> settings. My CPU is already at its recommended settings.
>>>
>>> Yousuf Khan
>
>> I did not raise the voltage back to where it was. Just enough to stop
>> the errors. I'm not saying that your errors are caused by the same
>> thing as mine. Just giving you something else to try.
>
> In this case you will likely stikk have errors on occasion.

Well, I consider a year without an optical drive error to be sufficient
to believe the problem is fixed. :-)

> You need to raise it to where the errors apprarently stop,

I did.

> and
> then a bit more.

I can't see the point to that, but if I did start to get some errors of
unknown origin I would definitely raise the voltage to see if it would help.

> Of coruse if the errors are non-critical,
> you do what you did. But you should be aware that this
> can also cause other errors that may not be as visible.

I'm having no other problems.

Charlie

[Paul]

Arno wrote:
> In comp.sys.ibm.pc.hardware.storage Yousuf Khan <bbb...@spammenot.yahoo.com> wrote:
>> On 23/03/2012 9:10 PM, Paul wrote:
>>> Yousuf Khan wrote:
>>>> On 23/03/2012 6:23 AM, Arno wrote:
>>>>> It is also possible that recitifers have gotten better.
>>>> Yeah, it had better be, or else I should be smelling smoke quite quickly.
>>> The only way a rectifier gets better, is by disappearing.
>>> In the picture here, the rectifier on the secondary is
>>> replaced by a MOSFET.
>>>
>>> ("Synchronous rectification")
>>>
>>> http://www.onsemi.com/pub_link/Collateral/AND8460-D.PDF
>
>> Interesting.
>
> Standard concept, but too expensive with transformers.
>
> Arno

Um, yeah, that's the transformer the ATX supply needs anyway.

Compare the picture in AND8460-D.PDF to Pavouk, for some inspiration.

Transformer T3 in the upper right of this picture, is the equivalent
of the transformer present in the Onsemi appnote. The synchronous
rectifier idea, would replace the diode pairs on the right of T3.

http://www.pavouk.org/hw/en_atxps.html

The advantage of the MOSFET, is no longer having to deal with the
diode equation, and a rising voltage drop across the rectifier,
as the current flow through it rises. If I run 20 amps through
a rectifier diode, and the drop across it is 1 volt, that's 20W
of heat. You then compare that to the channel resistance of the
MOSFET (and the I**2*R loss there), and the amount of energy needed
to drive the gate capacitance (it's a factor too). The Onsemi appnote
shows 91% efficiency at mid-load (Figure 50 on PDF page 26).

Paul

[Yousuf Khan]

On 24/03/2012 3:37 AM, larry moe 'n curly wrote:
> Bit-Tech.net says the 1GB Radeon 6870 uses from 128W - 247W. Power
> estimators aren't very good and usually give numbers that are way too
> high, and when XbitLabs.com took actual measurements, they got this
> (associated article goes into much more detail):
>
> www.xbitlabs.com/images/coolers/system-wattage/p40.png

I don't think the video is at issue at all, it's plugged into its own
private rail, and I've never had any problems with it. It's the storage
units that are having the problems.

Yousuf Khan

[Yousuf Khan]

On 24/03/2012 12:05 AM, Charlie wrote:
> I did not raise the voltage back to where it was. Just enough to stop
> the errors. I'm not saying that your errors are caused by the same thing
> as mine. Just giving you something else to try.

Well, I'll keep it in mind then. When all else fails, that's worth a
shot. But of course my first solution is a new PS.

Yousuf Khan

[Yousuf Khan]

On 24/03/2012 9:16 AM, Arno wrote:
> Ah, so you have a _theoretical_ result indicating possible errors.
> In that case you may want to redistribute your deicves a bit to
> the other rails, not replace the PSU. But note that typically,
> with a good quality PSU, 15% more load on one rail should not be
> an issue, as long as it is not permanent load and the device is
> overall not overloaded. You should also have had some overestimation
> in that calculation if you did it right.

I would, if I could, but I don't think there's any way to redistribute
them. Certain rails are dedicated to specific tasks, like motherboard
power, CPU power, and GPU power, and miscellaneous power for everything
else. It's miscellaneous power that is having problems now.

A single rail PS won't have this issue. Either everything will be
underpowered, or nothing will be.

Yousuf Khan

[Rod Speed]

Yousuf Khan wrote

I dont believe there is any evidence that you do have an underpowered rail.

The obvious way to prove wherther you do or not is to calculate the rail
CURRENTS using the datasheet values for the startup currents of the hard drives.

It would be worth trying any power supply you have to hand,
to see if that makes those optical drive errors go away.

You can even get the power supply from one of the operations like egghead
that do allow you to return the supply if you find it makes no difference to the
optical errors if you dont actually have a spare power supply handy or borrowable.

[shawn]

On Wed, 21 Mar 2012 18:30:38 -0400, Paul <nos...@needed.com> wrote:





>I don't own a copy of IEC60950, so I can't copy/paste
>the appropriate part. And the last time I looked, I couldn't
>find a copy "floating" on the web. The keyword "SELV" comes
>to mind, but that's about all I remember now.
>
http://www.freetechebooks.com/file-2011/iec-60950-pdf.html

[larry moe 'n curly]

Does the Zalman really have 4 separate rails, which would require at
least 4 separate windings for the +12V rails, or does it just have 4
separate current sense lines? Because JonnyGuru.com has found that
many PSUs advertised as being multirail have all the +12V lines
connected to the same place on the circuit board. Also the video
card probably won't be as sensitive to fluctuations from the +12V
because it has its own voltage regulator. Disk drives do, too, for
some voltages, but I don't know about the +12V for the motors.

[David]

Nice try, but it's only the first few pages.
IEC doesn't let this one out without paying for it.

Here's some pages that give you the gist of what's in the spec:

http://www.i-spec.com/IEC_60950/iec_60950.html

but to get the detailed requirements, you have to buy the spec.

SELV refers to circuits that are separated physically and electrically
from the other circuits, and do not carry a voltage more than 60V DC, or
42.5V peak AC.

[Yousuf Khan]

On 25/03/2012 8:02 AM, larry moe 'n curly wrote:
> Does the Zalman really have 4 separate rails, which would require at
> least 4 separate windings for the +12V rails, or does it just have 4
> separate current sense lines? Because JonnyGuru.com has found that
> many PSUs advertised as being multirail have all the +12V lines
> connected to the same place on the circuit board. Also the video
> card probably won't be as sensitive to fluctuations from the +12V
> because it has its own voltage regulator. Disk drives do, too, for
> some voltages, but I don't know about the +12V for the motors.

I don't know, according to this:

http://www.zalman.com/eng/product/Product_Read.asp?idx=196

"Four Independent +12VDC Outputs
Four +12VDC rails supply power independently to the CPU, VGA,
motherboard, and peripheral components for the highest level of
stability and performance. "

But that could just be marketing speak.

Yousuf Khan

[Yousuf Khan]

The following review article seems to doubt that the four rails are
actually independent.

http://www.silentpcreview.com/article688-page1.html

Yousuf Khan

[Paul]

http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story2&reid=30

http://www.hardwaresecrets.com/article/Zalman-ZM600-HP-600-W-Power-Supply-Review/402/6

It could be a single transformer with four output windings for +12V.
And four diode pairs (one pair per three legged package) for rectification
on the outputs. There are no closeup shots of the solder blobs on the wire
loom area, to see whether the 12V outputs are joined after the rectifiers
or anything.

The second reviewer, seems to be using a load tester with only two 12V loads
to use for the four outputs. The first reviewer is using a strange
loading pattern, which helps make 12V2 and 12V4 look like they're connected
together (identical voltages).

Paul

[Rod Speed]

larry moe 'n curly wrote

> Yousuf Khan wrote

They dont, but dont need that either. The most that a rail sagging
a little does is see the drive take a little longer to get up to speed.

[Rod Speed]

Yousuf Khan wrote
> Yousuf Khan wrote

>> larry moe 'n curly wrote

>>> Does the Zalman really have 4 separate rails, which would require at
>>> least 4 separate windings for the +12V rails, or does it just have 4
>>> separate current sense lines? Because JonnyGuru.com has found that
>>> many PSUs advertised as being multirail have all the +12V lines
>>> connected to the same place on the circuit board. Also the video
>>> card probably won't be as sensitive to fluctuations from the +12V
>>> because it has its own voltage regulator. Disk drives do, too, for
>>> some voltages, but I don't know about the +12V for the motors.

>> I don't know, according to this:

>> http://www.zalman.com/eng/product/Product_Read.asp?idx=196

>> "Four Independent +12VDC Outputs
>> Four +12VDC rails supply power independently to the CPU, VGA,
>> motherboard, and peripheral components for the highest level of
>> stability and performance. "

>> But that could just be marketing speak.

> The following review article seems to doubt that the four rails are
> actually independent.

> http://www.silentpcreview.com/article688-page1.html

You can check if they are just by opening the case and see
if all the 12V wires are all soldered together. I doubt they are
tho with a brand name like Zalman.