Re: 32bit OS cannot see 4GB of RAM on modern chipset

Peter Wieland from MS already answered this. This is a policy limitation on
XP 32 and Vista 32 to only be capable of 32bit physical addresses.

--
Maxim Shatskih, Windows DDK MVP
StorageCraft Corporation
maxim@xxxxxxxxxxxxxxxx
http://www.storagecraft.com

"Francis Robert Friel" <FrancisRobertFriel@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in
message news:4DA1D44D-4CAD-4140-B4CC-6A427B8DD93B@xxxxxxxxxxxxxxxx


"Tim Roberts" wrote:

"Maxim S. Shatskih" <maxim@xxxxxxxxxxxxxxxx> wrote:

I have a machine built on Intel G33 chipset (Asus P5K-V mobo).

64bit OS (2003 R2 SP2 Ent) sees all 4GB of really present RAM.

32bit OS (XP SP2 Pro) sees only 3.24GB of RAM, with PAE on.

Why is this? Any chances of fixing this by tuning some OS registry
settings
or the BIOS settings?

Alexander is right. You actually got relatively lucky; I have one
motherboard with 4GB installed, and XP 32-bit only sees 2GB. It all has to
do with the way the BIOS assigns the address space.
--
Tim Roberts, timr@xxxxxxxxx
Providenza & Boekelheide, Inc.


This is because XP can only reports 2GB of memory. The kernel takes the
rest, although we know it will never use it. Anyway this site will give you
specifics on memory levels for different versions of Windows.


http://msdn2.microsoft.com/en-us/library/aa366778(VS.85).aspx#physical_memory_limits_windows_xp

Please note the following statement on the page.

"Addresses near the 2-GB boundary are typically used by various system DLLs.
Therefore, a 32-bit process cannot allocate more than 2 GB of contiguous
memory, even if the entire 4-GB address space is available. "

.

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