Shuttle SD37P2 - Vista RC1 (32-bit) only see's 2GB

[Guest]

I'm having trouble getting 32-bit Vista to recognize all of the RAM in my
Shuttle SD37P2 "Conroe" system:

A clean install of 32-bit Vista RC1 (build 5600) only recognizes 2GB of RAM
on a 4GB Shuttle "SD37P2" system.

A clean install of 64-bit Vista RC1 (build 5600) on the same iron recognizes
the entire 4GB of RAM.

The Shuttle SD37P2 has the latest available BIOS SD37S022, dated 2006/07/06,
an Intel Core-2-Duo E6700 processor, and 4GB of ECC DDR2 RAM (as 4 sticks of
1GB each) The BIOS recognizes all 4GB of RAM in dual-channel mode and
displays the correct RAM size in SETUP.

The Shuttle BIOS has a setting for a "memory-hole" - which does NOT affect
the amount of RAM seen by 32-bit Vista - setting it to "enabled" or
"disabled" seems to have no effect on the result.

I would rather run the 32-bit version at least for the near term as most of
my 3rd-party software won't run on 64-bit.

Any suggestions or ideas welcome!

 

[Kerry Brown]

Every 32 bit version of Windows has this problem. It's not a Windows
problem. It's a limit of a 32 bit CPU. There is only 4 GB of memory that can
be directly addressed by the CPU. Peripherals need an address that maps into
the 4 GB space so the motherboard reserves some of the space for it's own
use in addressing these peripherals. Some very fancy motherboards use tricks
to map this up above 4 GB but it's very rare, mostly found on older server
boards from before 64 bit CPUs existed. Go into the Device Manager - View -
Resources by type. Expand the Memory branch. All that is memory addresses
used by the motherboard and peripherals.

 

[Guest]

Kerry,

Thanks for your quick response. I agree and I think I understand what you
are saying, namely that the 32-bit version of OS (Vista or WinXP) consider a
32 bit CPU regardless of the real hardware, because I have an Intel
Core-2-Duo E6600, and a compatible Intel mother board that do not have this
limitation.
Am I correct in saying that?

Thanks,

 

[Colin Barnhorst]

Correct. It is a simple arithmetic problem of how many addresses there are
with 32bit operating systems. Running a 64bit OS on the same hardware gives
you far more addresses mathematically. Vista x64 business editions and up
address 128GB directly.