Computer completely shutting down during gameplay - PSU not enough?

[kaic59]

I recently upgraded my rig with a Radeon HD 7970 (not overclocked), and had no problems with anything for a few weeks. Now, when I try to play certain games (that I hadn't played before so they may require more GPU power usage) the computer will just shut off completely with no warning and won't reboot unless I pull the plug and plug it in again. I have a brand new EVGA 750w power supply that I tested shortly afterwards and all tests seem to indicate it isn't faulty.

Is 750w enough? At the time I thought it was overkill as my system only said it would need about 550w or so.

specs:
AMD FX 8320 eight-core 3.5ghz
Gigabyte 990fxa-ud5 mobo
16gb ddr3
AMD radeon hd 7970

Only 1 monitor, 1 ssd, 1 regular hdd, and a cd-rw.

I would lean towards a faulty PSU, but why does it have no issues with other programs/games and only these two?

 

[AxlFone]

Is it this psu?

This did have issues with crosload tests but it was good enough.
Maybe you have bad vido card? I remember that some 7 serie crds do have some issue. But think it was on some 7870 or 7950 cards.

Try first uppgrade the video card drivers.

Was going to asr same thing as the tiny voice.

EVGA makes good enough psu.
http://www.techpowerup.com/reviews/EVGA/NEX750G/

 

[tiny voices]

EVGA does NOT make good PSUs at all. It could definitely be that.

Also, what are your max load temps for the CPU/GPU?

 

[ps3hacker12]

EVGA does NOT make good PSUs at all. It could definitely be that.

Also, what are your max load temps for the CPU/GPU?

Usually this is true, but some of their superNOVA range are actually rated to be pretty good.