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Last year I built a Core i7 920 system based on the ASUS P6T Deluxe motherboard. I have 3x1GB of DDR3 (triple-channel configuration), but only 2GB is being reported by: Windows XP, CPU-Z, the BIOS. Is this a hardware problem, or is the third gigabyte of RAM being reserved by the system for video card-related stuff? The video card has 512MB of RAM.

I realize that 32-bit Windows XP is not the ideal operating system for more than 2GB of RAM, but from what I've read it should be reporting at least 2.5GB.

chaos
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Scott Vander Molen
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5 Answers5

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If the BIOS is reporting 2Gb, then it's a hardware or BIOS problem, nothing to do with XP.

First thing I'd do is try the RAM two sticks at a time to see whether they're all good. Second thing would be checking if a BIOS upgrade is available.

chaos
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3

Double check what the BIOS is reporting. I suspect that your memory is actually there, but remapped over the 4GB limit: a 32bit OS will be able to see only 2GB, the BIOS should report the correct amount of memory though.

Your memory map might something like:

0-2GB physical memory
2-4GB hole for MMIO
4-5GB physical memory

My P5B-E does the exact same thing, but I'm running a 64bit OS...

2

I have used a XP Machine (32 bit) with 4 GB so i know that it supoprts upto 4 GB. since you are saying that BIOS is also reporting it as 2 GB , this should be a hardware problem, you probably need to test the slots or do some switching of the RAM modules to identify the faulty one.

Dinesh Manne
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In the bios, there should be a setting for dual or triple channel memory.

Ryaner
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Try enabling the /3GB switch in your boot.ini.

http://support.microsoft.com/kb/833721

Sören Kuklau
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