Hi there.
I have an A7V333 Motherboard with an XP2000+. I have discovered that when I have two memory modules (Matrox 512MB PC2700) in the slots, I experience system crashes. I have consulted my supplier who was not much help. They suggested that I upgrade the bios, or try other supported memory modules. (they were not offering to try this for me.) I had already checked my bios version and have the most recent installed.
The problem I have is this:
If there is one 512MB memory module installed, the system runs like a dream.
If there are two 512MB memory modules installed in Slot 1 and Slot 2, the system can be induced to crash by going to the windows XP update site and trying to select updates. This can be reproduced on demand and does not happen with only one memory module.
If I have two memory moudules installed in Slot1 and Slot 3, then I have the same problems as Slots 1&2
When the two memory modules are in Slots 2 & 3, the machine will actually run ok for a short period of time, however if you do something that uses lots of memory, like playing a game, the system will eventually crash or just shutdown.
My belief is that the is a problem with my mother board's memory slots, however I do not know how to have the supplier accept this. (they do not seem too interested in helping.) I am also willing to get them to supply me with supported memory, however I cannot find certified memory for this motherboard above 256Mb. Since I can only have 3 modules, I do not see how I can obtain my requirement of 1Gb with this memory.

As I mentioned, it works all fine with the one memory module, and I have tested both modules, and infact had one replaced as it was faulty. I am quite convinced that both modules I have are fine. I should also point out that I have used an ESD strap and workmat whenever working on my system. The machine is also protected by a UPS so power surges are out too.
Some more details about my System:
Lian-Li case with plenty of fans and no heating/cooling issues.
400Watt power supply
Operating System: Windows XP
LeadTeak Winfast 250 (ti4600) GeForce 4 video card
Pioneer CD/DVD
Adaptec 3940 SCSI Card
SMC Ethernet Card
Creative Labs Platnium 5.1 Sound card
2 IDE drives and 1 SCSI drive.

Has anyone else seen / heard of an issue like this? Have people tried more that 512MB in this type of combination? I have sent the same details to ASUS via e-mail twice now, and not had any sort of response, so either if is stuffed, or they do not understand customer support. One really anoying detail is the certified memory list! ASUS only has 256MB DDR modules listed which makes getting the max memory impossible. If you have / know / use other brands of 512MB DDR PC2700 memory in an ASUS, I would appreciate to know which brands and why you have selected them. I am at a loss at the moment as to how to continue with this problem as my belief is that the motherboard is stuffed however ASUS don't seem to have a way of getting them to test my system and prove to me that is it ok!

Looking foward to your responses,

Dean.

I don't read posts / forums often, so I might not be able to respond after this if needed.

One solution could be the voltage supplied to the memory, or the CAS / CL timings on your memory. If the memory modules are different ( not the same exact module ) then the timings may need to be set differently. If you have two ram sticks running at CL2, but one of the sticks is only rated for CL2.5 you would have to run both at CL2.5. Is the ram set by SPD in the bios? You should check to make sure. If not, and you do have two memory modules with different CL timings, try putting the slower one in the first memory bank.

That may be the cause of your problems, and I hope I helped in some way.