Computer shuts down then starts again

[Wries]

Hi

Hesitant to call it a reboot but well in a way it kind of is. My PC (sig) started doing this yesterday, all of a sudden it powered off completely and then started again. It then continued doing this ritual through the rest of the day at inconvenient times.

I can reproduce the problem quite easily by running prime or IBT. Heavy load makes it crumble within 10 minutes apparently. I have already removed the overclock on the CPU, it's back to stock clocks and settings. There's also not any temperature issue anywhere. Still it shuts down. Updated to the latest BIOS during troubleshooting.

I THINK it's one out of three things. The 2600K just continuing to prove that it came out of the worst batch of SB's. The ASUS P8Z68 Deluxe motherboard showing it's not worthy of its name. OR, and this would be the most convenient, the power supply, Corsair HX 750W not being able to cope anymore for some reason.

I'm hoping that it is the PSU because I have a Corsair VX 450W spare to use during RMA. But I am at the moment stressing the GPUs (folding@home) and the PC is not shutting down even though the GPUs should pull quite a lot of power at the moment. Might be a problem with just the 8-pin that supplies power to the CPU, does that make sense?

There's also the problem if it's not the PSU, I don't think I have any way to tell if it's the CPU or the motherboard in that case.

Any input will be appreciated

---------- Post added 2012-03-26 at 10:29 PM ----------

Forever alone I see

Well I unplugged the computer completely for a couple of hours and since I plugged it back in I have not been able to replicate the issue. Fingers crossed it was such an easy fix and that it won't happen again.