I was in thee middle of playing a game that isn't very demanding and my PC turned itself off without warning. It was the first game I have played after installing my new Gigabyte 7950 (Upgraded from Power Color 7870 MYST) and Corsair H55 CPU cooler. I'm a noob at PC building but my first guess was the PSU couldn't handle the load. When building everyone said to get a 500w because it would be more than enough but I got a 650w just to be sure so do I need to upgrade again?