ok so i built a pc a year ago, core i5 2500k, aftermarket cooler, asus p8p67-m pro board, corsair hx 850, 12 gb ram, ssd and a hdd, 2x gtx 660 ti. most times when im playing a game, usually in 1080p, my pc freezes and restarts, freezes mid game. it did it when i had 460's, then i got 660's, and same thing, so i upgraded from 4 gb ram to 12 to see if that fixed it and nothing. then i upgraded from a corsair 600 to a 850. and still does it, im ready to take a hammer to this thing. ive monitored temps and gfx and cpu stay in mid 60's sometimes high 60's. so im good there. what else could this be?