Use 3GB or 4GB RAM in 32 bit OS?
Daniel G.
I own a Dell dimension 8400 with 1 GB of RAM running windows XP SP 2
and also just bought a Gateway ML6720 laptop with 1 GB of RAM running
Windows Vista home premium. I believe the Dell machine as for memory
slots in the Gateway 82 memory slots. I'd like to bring both these
machines up to 4 GB of RAM but read this isn't possible in a machine
running a 32-bit OS, I read this at
http://www.crucial.com/systemscanner/index.aspx. It said, "How much
memory your Windows OS will recognize depends on which version of
Windows you are running. 32-bit versions of Windows will see (and
utilize) only 3GB or 3.5GB. To utilize more memory, install a 64-bit
version of your OS." My question is, can I install 2 GB in one slot
and 1 GB in the other available slut to make up the 3 GB or would I
have to install 2 GB of RAM in each available slot even though the OS
would only recognize 3 GB? I ask because a friend of mine said that
mixing RAM chip sizes really impedes the performance of a PC. Also,
some chips are labeled PC2-3200 and PC2-6400 etc. I understand these
denote RAM speeds? I'll be using Dragon Dictate heavily on both
machines and am wondering how big a difference it would make in
performance to get chips with a very high speed rating such as
PC2-6400? Thanks in advance for any info you can provide!
Ruy
Ruy
Arno Wagner
> On Mon, 24 Mar 2008 14:17:33 -0400, Daniel G.
> <Quad...@REMOVETHISoptonline.net> wrote:
>>Hi all,
>>I own a Dell dimension 8400 with 1 GB of RAM running windows XP SP 2
>>and also just bought a Gateway ML6720 laptop with 1 GB of RAM running
>>Windows Vista home premium. I believe the Dell machine as for memory
>>slots in the Gateway 82 memory slots. I'd like to bring both these
>>machines up to 4 GB of RAM but read this isn't possible in a machine
>>running a 32-bit OS,
> IF your MB supports 4 gigs, you CAN have that much,
> but Windows 32 bit won't use all 4 gigs, only about 3 gigs.
It is not that bad. You get around 3.7GB of 4GB with 32 bit
Windows XP (or Linux, or any other 32 bit OS). The missing
space is 1MB for the legacy space and 256MB for the
PCI graphics I/O window, and so you loose about 25% of the
last GB.
Arno
Yousuf Khan
>> IF your MB supports 4 gigs, you CAN have that much,
>> but Windows 32 bit won't use all 4 gigs, only about 3 gigs.
>
> It is not that bad. You get around 3.7GB of 4GB with 32 bit
> Windows XP (or Linux, or any other 32 bit OS). The missing
> space is 1MB for the legacy space and 256MB for the
> PCI graphics I/O window, and so you loose about 25% of the
> last GB.
XP sees 3.12GB out of my 4GB on my system.
Yousuf Khan
Arno Wagner
Hmm. There seem to be differences.
Arno
Rat River Cemetary
> Hmm. There seem to be differences.
>
> Arno
Because it depends on your hardware configuration. My video card is
512mb so it needs 512mb of address space, a 256mb card would need 256mb
of address space. I only have 3.0GB out of 4GB available to programs.
When I did have a 256mb vid card it showed 3.25GB of ram available.
Arno Wagner
Interessting. I seem to have 3.46GB with a 640MB video card under
Linux. No idea what I have under Windows.
Arno
Nate Edel
It varies by motherboard and in some cases, by what video card you've got.
--
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preferred email |
is "nate" at the | "I do have a cause, though. It is obscenity.
posting domain | I'm for it." - prologue to "Smut" by Tom Lehrer
Yousuf Khan
According to Microsoft, the maximum that it should see is only 3.12GB,
as I reported. It's the same for 32-bit Vista or XP.
"If a computer has many installed devices, the available memory may be
reduced to 3 GB or less. However, the maximum memory available in 32-bit
versions of Windows Vista is typically 3.12 GB."
http://support.microsoft.com/kb/929605/en-us
Yousuf Khan
Rat River Cemetary
> Interessting. I seem to have 3.46GB with a 640MB video card under
> Linux. No idea what I have under Windows.
>
> Arno
What other hardware do you have though? I think drivers take up address
space too. I'm not positive how it works but everything loaded into
memory needs address space?
Rat River Cemetary
> "If a computer has many installed devices, the available memory may be
> reduced to 3 GB or less. However, the maximum memory available in 32-bit
> versions of Windows Vista is typically 3.12 GB."
> http://support.microsoft.com/kb/929605/en-us
>
> Yousuf Khan
Maybe I got the exact figure wrong then but I thought I used to have
3.25GB when using a 256mb video card. Doesn't matter, 3GB of usable ram
is still better than 2GB and I do have some games that use up a lot of
ram. I should switch to Vista 64bit but I still prefer XP for gameing
with so only use Vista on another PC for internet stuff and digital
imaging etc. That computer only has 2GB of ram anyway.
Yousuf Khan
> Maybe I got the exact figure wrong then but I thought I used to have
> 3.25GB when using a 256mb video card. Doesn't matter, 3GB of usable ram
> is still better than 2GB and I do have some games that use up a lot of
> ram. I should switch to Vista 64bit but I still prefer XP for gameing
> with so only use Vista on another PC for internet stuff and digital
> imaging etc. That computer only has 2GB of ram anyway.
I doubt the whole 640MB of video memory is fully mapped to the system
memory. My guess is that they probably just map perhaps 128M at a time,
and slide through the video memory 128MB at a time.
As for my system, I use a 64-bit Ubuntu Linux on another partition.
Ubuntu sees only 3.9GB of my 4.0GB, but that's because I got an
integrated graphics, and 128MB of it is shared with the video. If I had
a discrete graphics, then I could turn off my integrated graphics, and
the whole 4.0GB would be used by the system.
Yousuf Khan
Franc Zabkar
finger to keyboard and composed:
My Internet PC is an old socket 7 box with a Diamond Stealth III S540
PCI card. Win98's Device Manager shows that it is using the following
memory resources:
FFA80000 - FFAFFFFF --- 512KB
F0000000 - F7FFFFFF --- 128MB (video RAM ???)
08020000 - 0802FFFF --- 64KB
000C0000 - 000CAFFF --- 44KB (video ROM BIOS extension)
000B0000 - 000BFFFF --- 64KB (video RAM below 1MB)
000A0000 - 000AFFFF --- 64KB (video RAM below 1MB)
Lavalys Everest tells me that the video adapter has 32MB of RAM which
leads me to wonder why the card's memory address space (128MB) is so
large.
- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.
Rat River Cemetary
> I doubt the whole 640MB of video memory is fully mapped to the system
> memory. My guess is that they probably just map perhaps 128M at a time,
> and slide through the video memory 128MB at a time.
512mb video memory and not 640mb. My Asus P5K mb has some option for
mapping memory when you have 4GB installed on 32bit OS but not sure what
it does exactly. I have it enabled though.
Yousuf Khan
> My Internet PC is an old socket 7 box with a Diamond Stealth III S540
> PCI card. Win98's Device Manager shows that it is using the following
> memory resources:
>
> FFA80000 - FFAFFFFF --- 512KB
> F0000000 - F7FFFFFF --- 128MB (video RAM ???)
> 08020000 - 0802FFFF --- 64KB
> 000C0000 - 000CAFFF --- 44KB (video ROM BIOS extension)
> 000B0000 - 000BFFFF --- 64KB (video RAM below 1MB)
> 000A0000 - 000AFFFF --- 64KB (video RAM below 1MB)
>
> Lavalys Everest tells me that the video adapter has 32MB of RAM which
> leads me to wonder why the card's memory address space (128MB) is so
> large.
I think the old DOS-based Windows OSes used a different memory
management scheme. Back then they used to map the memory mapped i/o
devices to the range between 640KB and 1MB. I think with the newer
Windows, that's all remapped in the range between 3GB and 4GB.
The whole missing 4th Gigabyte issue is reminding me of the days of the
transition from 16-bit to 32-bit os, when people were running into the
same issues, except at lower address ranges. History doesn't repeat
itself, it just rhymes.
Yousuf Khan
Franc Zabkar
finger to keyboard and composed:
>Franc Zabkar wrote:
The following memory resources are reported by msinfo32.exe in a P4
Windows XP box. You can see that the NVIDIA graphics device still
utilises the 0xA0000-0xBFFFF memory address range below the first MB.
If I understand things correctly, then the maximum amount of memory
that could be available to Windows XP in a fully populated system
would be 0xDC800000, ie 3.445 GB.
[Memory]
Resource Device
0xA0000-0xBFFFF PCI bus
0xA0000-0xBFFFF Intel(R) 82865G\PE\P Processor to AGP
Controller - 2571
0xA0000-0xBFFFF NVIDIA GeForce FX 5200
0x20000000-0xFFFFFFFF PCI bus
0xFC900000-0xFE9FFFFF Intel(R) 82865G\PE\P Processor to AGP
Controller - 2571
0xDC800000-0xEC7FFFFF Intel(R) 82865G\PE\P Processor to AGP
Controller - 2571
0xF0000000-0xF7FFFFFF Intel(R) 82865G\PE\P Processor to AGP
Controller - 2571
0xFD000000-0xFDFFFFFF NVIDIA GeForce FX 5200
0xE0000000-0xE7FFFFFF NVIDIA GeForce FX 5200
0xFEBFFC00-0xFEBFFFFF Standard Enhanced PCI to USB Host Controller
0xFEAFFC00-0xFEAFFCFF Lucent Win Modem
0xFFB80000-0xFFBFFFFF Intel(r) 82802 Firmware Hub Device
0xFFF80000-0xFFFFFFFF Intel(r) 82802 Firmware Hub Device
0xFEC00000-0xFEC00FFF Motherboard resources
0xFEE00000-0xFEE00FFF Motherboard resources
0xFED20000-0xFED9FFFF Motherboard resources
0xFFEFFC00-0xFFEFFFFF Intel(R) 82801EB Ultra ATA Storage Controllers
0xFEBFF800-0xFEBFF9FF SoundMAX Integrated Digital Audio
0xFEBFF400-0xFEBFF4FF SoundMAX Integrated Digital Audio
0x0000-0x9FFFF System board
0xC0000-0xDFFFF System board
0xE0000-0xFFFFF System board
0x100000-0x1FFFFFFF System board
phil-new...@ipal.net
The displaced RAM gets mapped above the 4GB line. A kernel with PAE mode
can access all of up to 64GB (and possibly 128GB with a hack). So if you
have a baord that can do 64GB and you put 64GB in it, you will then be
back to the problem of losing a sub-GB chunk of memory. People will be
whining about this problem a lot in a few years :-)
See also:
http://en.wikipedia.org/wiki/Physical_Address_Extension
--
|---------------------------------------/----------------------------------|
| Phil Howard KA9WGN (ka9wgn.ham.org) / Do not send to the address below |
| first name lower case at ipal.net / spamtrap-200...@ipal.net |
|------------------------------------/-------------------------------------|
Arno Wagner
> In comp.sys.ibm.pc.hardware.misc Rat River Cemetary <de...@rat.here> wrote:
> | Arno Wagner wrote:
> |
> |> Interessting. I seem to have 3.46GB with a 640MB video card under
> |> Linux. No idea what I have under Windows.
> |>
> |> Arno
> |
> | What other hardware do you have though? I think drivers take up address
> | space too. I'm not positive how it works but everything loaded into
> | memory needs address space?
> The displaced RAM gets mapped above the 4GB line. A kernel with PAE mode
> can access all of up to 64GB (and possibly 128GB with a hack).
Take care though, that this does potentially slows down your system.
I turned it off again, because Opera became quite slow under
certain conditions (high memory load).
> So if you
> have a baord that can do 64GB and you put 64GB in it, you will then be
> back to the problem of losing a sub-GB chunk of memory. People will be
> whining about this problem a lot in a few years :-)
Yes, very likely ;-)
Yousuf Khan
> The displaced RAM gets mapped above the 4GB line. A kernel with PAE mode
> can access all of up to 64GB (and possibly 128GB with a hack). So if you
> have a baord that can do 64GB and you put 64GB in it, you will then be
> back to the problem of losing a sub-GB chunk of memory. People will be
> whining about this problem a lot in a few years :-)
>
> See also:
> http://en.wikipedia.org/wiki/Physical_Address_Extension
If you have a newer processor with the hardware Data Execute Prevention
(DEP, aka No Execute bit, NX-bit) feature, Windows automatically puts
you into PAE mode, even if you don't have more than 4GB installed on the
system. That's because AMD (who created the mechanism, followed by
Intel) decided that only the newer PAE-style page tables and newer
should have this feature implemented in them.
But even though PAE is enabled, 32-bit Windows still doesn't remap the
missing ram between 3-4GB. I guess it just finds it not worth the
effort. 64-bit Windows will remap it and use it though.
Yousuf Khan
Rat River Cemetary
> But even though PAE is enabled, 32-bit Windows still doesn't remap the
> missing ram between 3-4GB. I guess it just finds it not worth the
> effort. 64-bit Windows will remap it and use it though.
>
> Yousuf Khan
Yea, I have PAE enabled in the mb and it still shows only 3GB of 4GB in XP.
L Alpert
"Rat River Cemetary" <de...@rat.here> wrote in message
news:UvPGj.128282$pM4.120315@pd7urf1no...
I have a 512mb video card and XP shows 3.5 GB of memory.....must be
differences in hardware configurations....
Lee Waun
"Yousuf Khan" <bbb...@yahoo.com> wrote in message
news:47e9be20$1...@news.bnb-lp.com...
Xp sees 3.25GB out of 4GB on my system.
Yousuf Khan
>> XP sees 3.12GB out of my 4GB on my system.
>>
>> Yousuf Khan
>
> Xp sees 3.25GB out of 4GB on my system.
Interesting that you should mention this, I just took a look again and
now my system is showing 3.25GB too. I assume this has something to do
with the fact that I just installed a GeForce 8600GT into my system,
whereas previously I was using integrated graphics.
Also goes to show that discrete graphics frees up more memory for you
than integrated graphics.
Yousuf Khan
Lee Waun
Y present card has 512mb but the card before that had 256mb and my system
also showed 3.25gb. I bought the 4 gigs so I could upgrade to vista 64 but
it was so bad an OS I went back to XP. I clearly don't see my trying Vista
again now that my system is XP service pack 3.
YKhan
> Y present card has 512mb but the card before that had 256mb and my system
> also showed 3.25gb. I bought the 4 gigs so I could upgrade to vista 64 but
> it was so bad an OS I went back to XP. I clearly don't see my trying Vista
> again now that my system is XP service pack 3.
Yeah, I don't think the video ram actually takes up much system ram
footprint. The video ram is slid through the system ram footprint, in
small chunks, through a fixed-size graphics aperture.
As for why I got 4GB, I simply got it because it was on sale. :-)
I put in Ubuntu as my 64-bit OS, and I'm occasionally dual-booting
into it.
Yousuf Khan