I know everyone has heard the 680 vs 7970 argument a zillion times, but I'm having a very tough time deciding which of these specific cards to get. Which of the three will perform best in most games maxed out at 1080p, and which will overclock best? The 680 classified has the highest stock clock and leads me to believe that it will overclock better than the other two cards, but I could be wrong. And a couple more questions if y'all don't mind, can I get by overclocking any of these cards with a good 600w PSU, and will a i5 3750k bottleneck any of these gpu's? All answers are GREATLY appreciated, thanks