I can only use 1 DIMM of Corsair at a time - why?

[Lythe]

I found out last night that i can run World of Warcraft using only 1 DIMM (512) of Corsair XMS3200 DDR SDRAM (400MHz). If I put two in (seemingly in any configuration, in slots 1&2 or 1&3) I crash intermittendly. Why is this?

 

Here is some background...

I have an Albatron PX915P4C Pro, a nVidia 7800 GT video card (made by BFG Tech), 1.5gig (3x512) Corsair XMS3200 DDR SDRAM (400MHz), and 978 P4 3.2Ghz (200x16.0, CPU ID/UCOD:0F29/21).

Since I have upgraded to the video and motherboard I crash constantly while playing World of Warcraft or Battle Field 2. No specific type o' crash, some Error #132, some IRQ-less-than-or-equal some [insert name here].

I have run memory tests (memtest) which showed the RAM working properly, I have returned (RMA) both the video card and the motherboard for new ones and upgraded to 600 watt power supply. I have flashed the bios, it is now R1.37 and I am still getting these crashes. The CPU temperature and case temperature are fine, ~40c. I have Corsair 3200 RAM (2x512megs). I wonder if it is this causing the crashing. The bios states that the RAM is “DDR SDRAM: 400MHz (Dual Channel Mode Enabled)” and I have the two DIMMs in each of the colored slots (both are in the purple slots with the green slot between them and to the right). Is there a problem with the motherboard’s bios or chipset with this memory’s speed or latency or dual channel mode? Perhaps even with the P4’s Hyperthreading? Is there something I can change in the bios to stop these crashes?

 

Each RAM stick says:

 

"CMX512 -- 3200LL

XMS3205v1.2 0329048

XMS 3200

512MB 400MHz

2326-T1"

 

Also in the Bios, the "DRAM Timing Seletable" is "BY SPD"

x CAS LAT TIME 2.5

x DRAM RAS# TO CAS# DELAY 3

x DRAM RAS# PRECHARGE 2

PRECHARGE 2 DEALY (tRAS) 6

[RAM GUY]

Please try and set the memory voltage to 2,75 Volts and see if that will solve the problem. Also are all oft he modules the exact same part# and revision?