What resolution are you using? The best GPU will be largely dependent on that. The AMD 7900s only come into their own at 1440p+ resolutions. I also would not recommend an i7 for a gaming build. The CPU you picked has a small advantage over an i5 like the i5 3570k, and the premium you pay for it makes the little performance gain almost obsolete. Games can not yet use 4 extra hyper threads that it will give you.You also don't need 16gb of ram. It is a little overkill. 8gb should be best.