P5B-E only recognizes 2.68 GB of 4GB

[GaryD]

I just installed 4 X 1GB Corsair CM2X1024-6400 memory in my P5B-E motherboard, and it will only recognize 2688 MB (2.688 GB) of it. If I install only 2 sticks, all 2 GB are recognized. If in install 3 sticks, it recognizes only 2.688 GB. If I install the 4th stick, it doesn't recognize any more than with 3 sticks.

 

I've swapped sticks, thinking one or more of the modules are bad, but they all work fine if I only install 2, regardless which of the 4 slots I plug them into.

 

I want the MB to recognize all 4 GB even though right now I'm running Windows XP Pro 32-bit, and I know it will only see 3.25 GB or so of the 4 GB. But this problem is at the motherboard/bios level, since BIOS setup only reports the 2688 MB number.

 

I've installed the latest BIOS updates for the P5B-E and still no joy.

 

Is this memory compatible with my motherboard?

Would 2 X 2GB sticks work better than 4 X 1?

 

What am I doing wrong?

[Yellowbeard]

Look for an option called Memory Remapping and enable it.

[GaryD]

Look for an option called Memory Remapping and enable it.

 

Thanks, Mike! I saw the option, but I was under the impression you shouldn't enable it unless you are running a 64-bit OS. Was I misinformed?

 

Thanks again!

[Yellowbeard]

Thanks, Mike! I saw the option, but I was under the impression you shouldn't enable it unless you are running a 64-bit OS. Was I misinformed?

 

Thanks again!

This switch has no bearing on the OS. It simply affects how the chipset addresses memory. What your OS can do with it once the system boots is a seperate issue. Once your MOBO recognizes 4gb, then if you have a 32bit OS, your system will see between 2.75gb and 3.5gb depending on various factors. A 64 bit OS will recognize all of it.