[Poseidon]

damn - i've only 1 space for a fan

[Hollywood]

It's most most likely the RAM, or the power supply. I bet if you swapped out the video card and replaced it the system would still lock up. The reason I say this is because the RAM should show up with the rated frequency as default. If it doesn't, it is most likely because the RAM is actually rated lower then advertised (RAM is like a CPU, they are produced the same way, but depending on how stable they are under certain variables determines what frequency they can operate on).

I had a similar problem, and I have yet to really resolve it, but I have replaced everything with spare parts in my system and it still restarts while running benchmarks and some games. I purchased Geil DDR400 RAM, and it defaulted at 266. I ran memtest and it found no problems whatsoever, but the reviews at newegg were filled with similar problems. Buy a better brand of RAM, and try it out.

But unless you can swap out certain parts and troubleshoot you will never be able to determine what devices is causing the problem.

The best advice I can give is:

1) Run Mobo monitor in conjunction with Sandra Soft and burn in the CPU, check how hot the CPU gets under full load (not idle)

2) Download CPU-Z and to easily check the voltage and FSB currently applied to the CPU. You may have to bump up the voltage, but watch out for the heat increase.

3) Download Windows Memory Diagnostic from microsoft.com and create a boot disk to check your memory.

4) Unplug all devices from the power supply except the hard drive (and video card if necessary) and run a benchmarking app like aquamark3 or 3dmark01-03

5) Disable the sound card in device manager, or turn off hardware acceleration in dxdiag

6) If you think it's a heat issue on the Video Card, get a house fan if necessary just to test the card.

7) If you think it's a driver issue for the video card (uninstall the video drivers, unplug the internet connection, reboot into safe mode and run driver cleaner 2 (google it). Then use a registry cleaner and remove the device from device manager. Restart and install newest certified drivers.

8) Check out driverheaven.com, guru3d.com, or google for overclockers forums. There are similar stories there.

9) If you haven't, try formatting for the hell of it.

10) Bring it to a technician of you can't figure out what is wrong, it will save yourself a headache.

[Bazooka_Joe]

Could be overheating, or the overclocking of that RAM.