What's wrong with my pc? (PSU or GPU problem)

[rainmert]

I have a Corsair VS650 PSU for a year. I did not encountered any problems with it until last week. My computer started restarting whenever the gpu is under load. Sometimes i can play a game for 15 minutes without restarting but sometimes it restarts in couple of seconds. I'm not sure if the problem is about my gpu or psu. (GPU is Asus GTX 970)

I installed Furmark for better understanding the problem. But same as before my pc restarts itself after 10-15 minutes or 20-30 seconds. My max gpu temperature is 66 Degrees. Cpu temperature is normal too. So it doesn't look like an overheating problem. It's probably because my psu cannot provide enough power to gpu when it's under heavy load. But i'm really confused. Why it restarts sometimes after 15 minutes and sometimes after seconds? How can i know if the problem is about gpu or psu?

 

[Aeacus]

It's probably because my psu cannot provide enough power to gpu when it's under heavy load.

You answered it by yourself. Good job!

Corsair VS series is a low quality Tier four PSU.

Tier Four
Built down to a low price. Not exactly the most stable units ever created. Very basic safety circuitry or even thin gauge wiring used. Not for gaming rigs or overclocking systems of any kind. Avoid unless your budget dictates your choice.

PSU Tier list: http://www.tomshardware.co.uk/forum/id-2547993/psu-tier-list.html

I suggest you get a new Tier two PSU, preferably Tier one if you can afford it.

Anything from Seasonic is great. For your system, a 500W range will do just fine.
Here i suggest either S12II-520, M12II-520 EVO, S12G-550 or G-550.

 

[sizzling]

It's a very poor quality PSU, you got a year out of it before it started failing. Replace it immediately before it damages your PC but this time with a higher quality unit.