PC crash's when booting games and stress testing my GPU. GPU, motherboard or PSU problem?

Joshgibbs

Reputable
Dec 14, 2015
9
0
4,510
CPU: i5 4690K
Motherboard: MSI Z97 G55 SLI
RAM: 8GB
GPU: Radeon 280x 3GB
PSU: Antec high current gamer 850W HCG
Windows 8.1
Overlocked? Nope
PC is 1 year old.

Whenever I launch games it shuts off instantly and restarts 2 seconds later, usually as soon as I hit the menu. No error message or anything. It also crash's just as I start stress testing with Valley Benchmark. I'm guessing it's either the GPU or PSU but I don't know how to find out which one. Temperatures are not a problem at all, I even cleaned the PC very thoroughly. No success.

I took the graphics card out and could actually play counterstrike on high settings without any crash's, I just used the motherboards graphics. This same situation has happened to me before, but it completely disappeared after 5 days or so but now it has returned. I haven't made any major changes to my PC, software or hardware as of recent, so... Anyone know what piece of hardware is the culprit? Thankyou all for reading. :)

I've also tried using all 4 different sockets on my PSU for my graphics card's cables and I've also tried clearing the CMOS. No success I even tried using a different PCIE slot. Rip.