Use 3GB or 4GB RAM in 32 bit OS?

[Daniel G.]

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, 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]

Daniel G. escribió:

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, 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!

(e-mail address removed)

(e-mail address removed)

(e-mail address removed)

(e-mail address removed)

(e-mail address removed)

 

[Ruy]

Daniel G. escribió:

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, 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!

(e-mail address removed)

(e-mail address removed)

(e-mail address removed)

(e-mail address removed)

(e-mail address removed)

 

[Arno Wagner]

On Mon, 24 Mar 2008 14:17:33 -0400, Daniel G.

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]

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]

XP sees 3.12GB out of my 4GB on my system.

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]

Arno Wagner wrote:

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.

Interessting. I seem to have 3.46GB with a 640MB video card under
Linux. No idea what I have under Windows.

Arno

 

[Nate Edel]

Hmm. There seem to be differences.

It varies by motherboard and in some cases, by what video card you've got.

 

[Yousuf Khan]

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.

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]

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

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

 

[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

 

[Guest]

| 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). 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

 

[Arno Wagner]

In comp.sys.ibm.pc.hardware.misc Rat River Cemetary <[email protected]> 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.