New system build extremely unstable

[Ultraliner]

Hi everyone,

I just built a new system with the following specs:

Athlon64 x2 4200+ w/scythe ninja heatsink
Corsair TWINX2048-4000PT ram (2gb kit)
Asus a8n32-Deluxe motherboard
Antec NeoHE 430 PSU
eVGA Geforce 7900GT
Samsung 2504c sata hdd

I assembled everything, and booted the system. The first time it seemed to boot fine, and I was able to set the system time in the bios. Left everything else at default, and restarted.

The system POSTed fine, and I went into the bios again, at which point it froze. I restarted, and it did the same thing. It continued doing this for a while. I tried unplugging components one by one to see what might be causing it, but even when I took the system down to just mobo, video and ram, it still did this. Now I know there's a known bug with my model of power supply and asus motherboards, but it's supposed to have been resolved with PSU revisions built after 11/05. The serial number on mine indicates this, but I tried swapping out the PSU for a spare one I had just to be sure. The problem still occurred, which led me to believe that the PSU was not at fault.

I then removed one of the sticks of ram, and the system booted. I was able to install windows and the video card drivers. Then I tried running 4x cpuBurn to see what the temperatures would be like. Motherboard Monitor reported 41C stable for the CPU, but after about 5 minutes, the system just shut off.

I then ran memtest, which reported no errors for 67% of the tests, and then halted with an Inv_OP message, Eflag = 00010803. It did this consistently.

All voltages and timings on the motherboard were left at the default for all these operations. The Bios reported them as:

Vcore: 1.392 95% of the time, with occasional jumps to 1.424 (default sets it at 1.425)
3.3v: 3.232
5v: 4.865 - 4.892 (fluctuates)
12v: 11.904

CPU-Z reported the ram timings as: 3-4-4-10

I haven't tried plugging the second ram module back in. Does anyone have any ideas? Any and all suggestions would be very much appreciated.

Thanks!

 

[BadThad]

I then ran memtest, which reported no errors for 67% of the tests, and then halted with an Inv_OP message, Eflag = 00010803. It did this consistently.

RMA your ram.

 

[Ultraliner]

Well, I've found the problem. Turns out to be user error (isn't it always?). The ram I put in is spec'd at DDR500, but the mobo is spec'd at DDR400. It can be overcloced higher, but to do that you need to mess with the processor settings as well, which I, of course, didn't do (I left everything at stock). As soon as I set the memory frequency to 200mhz instead of 250, everything started working, but it still gave me memtest errors (in the same spot). Reading through the Corsair support forums led me to try turning off legacy USB support, which cleared up the memtest errors. I left it running overnight (9 iterations) and it passed them all. Now I can go and stress-test further.