Vista 32bit can't recognize all the memory

cavarpe · External Since: Dec 07, 2006 Posts: 2

I have an IBM Intellistation A Pro with 2 x Dual Core Opeteron's 275 with 4GB
of RAM. If I install Vista 64bit RTM I can see all the 4GB of RAM but If I
use Vista 32 bit I only see 2.8GB of RAM.

Have any body experience this?

Tom Lake · External Since: Feb 26, 2006 Posts: 407

"cavarpe" <cavarpe RemoveThis @discussions.microsoft.com> wrote in message
news:75F6C20F-8873-4BFD-A820-D1FA8E244DF4@microsoft.com...
>I have an IBM Intellistation A Pro with 2 x Dual Core Opeteron's 275 with 4GB
> of RAM. If I install Vista 64bit RTM I can see all the 4GB of RAM but If I
> use Vista 32 bit I only see 2.8GB of RAM.
>
> Have any body experience this?

Yes. It's common. A 64-bit OS can address much more than 4 GB so
the I/O and work areas can be moved out of the 4 GB address space.
A 32-bit OS has just 4 GB *total* addressability so the I/O and work
areas have to use some of that space. 2.8 GB sounds a bit low but you
may have a lot of peripherals, large video memory and large shared
area between the two processors.

Tom Lake

cavarpe · External Since: Dec 07, 2006 Posts: 2

My Card has it own build in memory (ATI FireMV 2400 PCIe). Is there anything
that I can do to fix this. I found issues with our applications in Vista
64bit. Is this something that Intel Systems don't have the issues versus an
AMD system?

"Tom Lake" wrote:

> "cavarpe" <cavarpe DeleteThis @discussions.microsoft.com> wrote in message
> news:75F6C20F-8873-4BFD-A820-D1FA8E244DF4@microsoft.com...
> >I have an IBM Intellistation A Pro with 2 x Dual Core Opeteron's 275 with 4GB
> > of RAM. If I install Vista 64bit RTM I can see all the 4GB of RAM but If I
> > use Vista 32 bit I only see 2.8GB of RAM.
> >
> > Have any body experience this?
>
>
> Yes. It's common. A 64-bit OS can address much more than 4 GB so
> the I/O and work areas can be moved out of the 4 GB address space.
> A 32-bit OS has just 4 GB *total* addressability so the I/O and work
> areas have to use some of that space. 2.8 GB sounds a bit low but you
> may have a lot of peripherals, large video memory and large shared
> area between the two processors.
>
> Tom Lake
>
>

Peter Meinl · External Since: Sep 03, 2006 Posts: 46

32bit Vista RC2 only sees 3 of 4GB memory installed on my Intel D975XBX
mainboard. Vista RC2 x64 sees all 4GB, so this seems not to be a mainboard
problem.
See Thread "Vista RC2 x86 PAE not working. Only sees 3 of 4GB memory" in
microsoft.public.windows.vista.installation_setup.

I opened a service request with Microsoft (SRZ061127002189) to get a
definitive answer.

Here a summary of their answer:
32bit Vista does by design not(!) use the full 4GB of physically installed
RAM.
Technically it could use 4GB (by using PAE to access the memory remapped by
the mainboard above the 4GB address boundary). By a marketing design
decision all Windows Vista 32bit editions are limited to 4GB address space.
Vista Starter ist limited to 1GB. "This is based on marketing decisions and
cannot be cheated with the PAE-Kernel."

I find it hard to believe that someone made such a marketing decision: I can
understand that MS limits physical memory of some Vista edtitions to 4GB. I
do not understand a design decision to not fully use this memory even though
it is technically possible. I assume there are technical or security issues
involved - but this is just my feeling and not based on facts.

Some background links:

Intel® Chipset 4 GB SystemMemory Support
http://www.polywell.com/us/support/faq/4GB_Rev1.pdf

Memory Limits for Windows Releases
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/memor...ase/mem
eleases.asp

Information regarding PAE-Kernel:
http://msdn2.microsoft.com/en-us/library/ms791485.aspx
http://www.microsoft.com/whdc/system/platform/server/PAE/PAEdrv.mspx

"cavarpe" <cavarpe.TakeThisOut@discussions.microsoft.com> wrote in message
news:75F6C20F-8873-4BFD-A820-D1FA8E244DF4@microsoft.com...
>I have an IBM Intellistation A Pro with 2 x Dual Core Opeteron's 275 with
>4GB
> of RAM. If I install Vista 64bit RTM I can see all the 4GB of RAM but If I
> use Vista 32 bit I only see 2.8GB of RAM.
>
> Have any body experience this?

Robert Moir · External Since: Nov 24, 2006 Posts: 445

cavarpe wrote:
> My Card has it own build in memory (ATI FireMV 2400 PCIe).

Yes but it still needs to use some of the memory space that is allocated to
RAM on your system, as do some other peripherals.

> Is there
> anything that I can do to fix this. I found issues with our
> applications in Vista 64bit. Is this something that Intel Systems
> don't have the issues versus an AMD system?

Without knowing the applications in question and how they work exactly, I'd
say it was very unlikely to be an "AMD vs. Intel" issue and far more likely
to be a "32bit vs. 64bit" issue. If the apps install their own drivers or
perform other similar tricks, then it may also be that these drivers are not
signed.

If you really need Windows Vista with 4Gb of physical RAM available, then
you should probably look at getting these apps to work with 64bit Vista.

Regards
Rob Moir.