CPU: i7 2600k running at stock 3.4gz
CPU Cooler: Thermalright Venomous X-RT
Mobo: Asus P8P76 Rev B3
GFX: Gefore GTX 460
So randomly, maybe once or rarely twice a week, my computer will just shut off as if i pulled the plug from the PSU and then power back on 4 seconds later. I replaced the PSU with a new 900w one, so its not that since the problem existed both before and after that. Obviously overheating was the first thing that came to mind. However, it will occasionally happen while not under load, and when I check the internals they are not unusually warm.
It happened most recently about 10 minutes ago while at, to my guess, a 8-13% load with 60% ram usage. I got these numbers from the BIOS immediately(10-20 seconds) after the shutdown.
The SAME EXACT THING has been happening to me for MONTHS. I've sent PRACTICALLY EVERYTHING to RMA already, spent over 200€ in travels / packages to send the parts to the store, only one thing left: THE MOTHERBOARD (And graphics card, but this one i already tested on another system, it worked flawless for 2 weeks).
It's exactly as you say, the computer will just shutdown and then a bit after start up, no mater if it is with overclock or at stock. My board is the same chipset as yours, however mine is a P8P67 Deluxe.
I can't right now say "send your board to RMA and it will be fine", since mine will only go out to RMA monday next week. But i'm practically 100% sure it's a board problem that you and i are having. DO you have any other board to test with? My problem is that no one i know has the same chipset as i am, so i can't test it .
Lets see if we can get out of this Sandy Curse once and for all!