PC2-6400 RAM is 400Mhz or 800Mhz?
bornfree
CPUZ tells me my ram (which is PC2-6400) has a max bandwidth of 400
Mhz. But on ebay I see this type of RAM quoted as running at 800Mhz.
Why? :S
Nick Le Lievre
news:f871506d-df0f-413f...@f47g2000hsd.googlegroups.com...
Its DDR double data rate so your 400mhz data rate is 800mhz double data
rate...
bornfree
<nicklelie...@jerseymail.co.uk.invalid> wrote:
> "bornfree" <justyouan...@xemaps.com> wrote in message
Errrrrrr..... Well I realise that... but ... errr... is it running at
400 or 800? :S
Lee
news:f871506d-df0f-413f...@f47g2000hsd.googlegroups.com...
at a guess CPUZ is telling you what your processors data bus is running at
which is a throughput of 400Mhz and your system is fsb is at 200mhz * 2? ram
is capable of 800mhz throughput.
Dr.Hal0nf1r£$
Possibly because you're running a dual-core CPU with dual-channel memory
configuration; therefore the two channels split the figure: For example I am
currently using a PC with an AMD Athlon 64x2 4000+ CPU and dual-channel
(2x1GB) 667MHz DDR2. Everest indicates that my RAM is running 333MHz per
channel/stick.
( Please excuse the non-technical explanation; I just got in from town.)
HTH
Nick Le Lievre
news:9AHmj.10031$PN2....@fe1.news.blueyonder.co.uk...
No its the SPD data telling him his RAM is PC2-6400 400mhz... its not
telling him the DDR speed of the RAM. If he wants to know the bus speed look
under the CPU section of CPU_Z... mine is at 375mhz and I know that with the
system memory multiplier of 2.0 that means its running at 750mhz or DDR2-750
it is slightly overclocked as under the SPD section where OP is looking it
says PC2-5300 333mhz or DDR 667.
Andrew Kressman
It's running at 400MHz. DDR RAM represents data on both the leading and
trailing edge of the clock cycle, therefore twice as much data can be
transmitted per MHz. That's why they quote an effective speed of 800MHz
when really it's clocked at 400MHz.
Nick Le Lievre
news:nbCdnV53WrI...@pipex.net...
With a default system memory multiplier of 2.0 its running at twice the bus
speed, he can see his bus speed by looking under the CPU section of CPU_Z...
if its 200 and the default memory multiplier of 2.0 is set then it will be
running at 400mhz, if the bus speed is 266 and the default multiplier is set
then it will be running at 533, if it says the bus speed is 333 and the
default multiplier is set then it will be running at 666mhz.... I think the
OP has a E6300 if so and not overclocking the bus speed should be 266 and
with the default multiplier of 2.0 this means the memory is running at
533mhz.... this is some way above its rated speed of 800... the only way he
could get that would be to run a bus speed of 400... or change the default
memory multiplier.
Nick Le Lievre
news:479b48c3$0$1341$834e...@reader.greatnowhere.com...
>>
>> It's running at 400MHz. DDR RAM represents data on both the leading and
>> trailing edge of the clock cycle, therefore twice as much data can be
>> transmitted per MHz. That's why they quote an effective speed of 800MHz
>> when really it's clocked at 400MHz.
>
> With a default system memory multiplier of 2.0 its running at twice the
> bus speed, he can see his bus speed by looking under the CPU section of
> CPU_Z... if its 200 and the default memory multiplier of 2.0 is set then
> it will be running at 400mhz, if the bus speed is 266 and the default
> multiplier is set then it will be running at 533, if it says the bus speed
> is 333 and the default multiplier is set then it will be running at
> 666mhz.... I think the OP has a E6300 if so and not overclocking the bus
> speed should be 266 and with the default multiplier of 2.0 this means the
> memory is running at 533mhz.... this is some way above its rated speed of
> 800... the only way he could get that would be to run a bus speed of
> 400... or change the default memory multiplier.
sorry the above should read "this is some way below its rated speed of 800"
bornfree
RAM 400Mhz
So FSB:DRAM 1:1
On the SPD tab of CPU-Z I notice that the latency figures seem to be
lower if the RAM frequency is 200Mhz.
Does this mean that by overclocking my RAM I have increased the
latency and made my system less responsive?
bornfree
Well... I never overclocked the RAM specifically... just the FSB and
the Ram came with it.
Nick Le Lievre
If your bus speed is 400mhz then your RAM will be running at 800mhz with the
default memory multiplier, forget what SPD says... my SPD says that my ram
is 333mhz but I know for a fact it is rated for 667mhz and I actually run it
at 750mhz (I know the memory multiplier is 2.0). It actually says the RAM is
running at 750mhz at POST, if you have a Gigabyte P35 board it should your
speed also. You need to find out what timings your RAM is capable of and
specifically set those in the BIOS, it could be CL5 @ 800mhz therefore
5-5-5-15 or it could be CL 4-4-4-12. I wouldn't worry too much about latency
it doesn't make *that* much difference.
bornfree
<nicklelie...@jerseymail.co.uk.invalid> wrote:
> "bornfree" <justyouan...@xemaps.com> wrote in message
How do I find that out?
John Jordan
> "bornfree" <justyo...@xemaps.com> wrote in message
> news:c1b55e8a-814a-4f2c...@c23g2000hsa.googlegroups.com...
>
>> 400 or 800? :S
>
> It's running at 400MHz. DDR RAM represents data on both the leading and
> trailing edge of the clock cycle, therefore twice as much data can be
> transmitted per MHz. That's why they quote an effective speed of 800MHz
> when really it's clocked at 400MHz.
Yeah. With DDR2, the memory chips themselves actually run at half the
bus clock speed, so for PC2-6400 you have an 800MHz data rate, a 400MHz
memory bus clock, and DRAM chips running at 200MHz.
--
John Jordan
Nick Le Lievre
>
> "You need to find out what timings your RAM is capable of"
>
> How do I find that out?
Just set them to 5-5-5-15 to be safe... but if you want to set them to
4-4-4-12 then download Prime95 torture test after and run for 8 hours to
stress test at those settings. If it errors then back them off to 5-5-5-15.
mahmou...@gmail.com
can i use 4gb-ddr2-800 ?
Rob Morley
This is a useful tool for checking compatibility:
http://www.crucial.com/uk/systemscanner/
Bob Martin
Rob Morley
Bob Martin <bob.m...@excite.com> wrote:
> in 227623 20140117 212152 Rob Morley <nos...@ntlworld.com> wrote:
> >On Fri, 17 Jan 2014 13:15:04 -0800 (PST)
> >This is a useful tool for checking compatibility:
> >http://www.crucial.com/uk/systemscanner/
>
> Windows only (needless to say).
bottom of that page you'll find the "Crucial Memory Advisor" - just
select your motherboard details from the drop-down lists. On this
system "sudo lshw -short" provides the necessary information.