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.
AMD FX 8320 eight-core 3.5ghz
Gigabyte 990fxa-ud5 mobo
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?