NOW: SAME:EVGA P55 FTW
SAME:Intel i7 LGA 1156 860 SAME:Corsair H50 CPU Cooling
Corsair Vengeance 8GB (4GBx2)
Gigabyte ATI R9 270 2GB (I know that this one is PCI Express 3.0) SAME: Thermaltake Toughpower 750W
G19 Keyboard G700 Mice
Now when I am playing for example in Test Range on BF4, it lags (even in low settings), also on online servers. FSX runs good. BUT on BOTH games that I tried in about 20-70min the computer just shutdown by itself. I put the EVEREST Ultimate edition and none of the CPU or VGA sensors go over 50C. All other temperatures are kept normal usually 37C.
i had a problem when i built my pc with the memory timings (cas , latency etc.) and it was shutting down. I had to manually set them through BIOS. It took me a month to figure it out. But i guess you have already done it?