Oh its this thread again.
1] A APU is not a high end part, you don't get any gains from it using higher end Radeon cards, but essentially strip the APU of its purpose. Consider the APU a separate project in conjunction to FX which work hand in hand until AMD is fully HSA. So no I don't suggest you pair a 5800K with a HD 7950 but would suggest a FX processor from the AMD front, preferably a FX 8000 chip.
2] Gaming performance differentials are abysmal yet harked on like a fish wives tale.
http://www.techpowerup.com/reviews/AMD/FX8150/11.html I am struggling to find benches which give Max, Min and average frame rates which severely discredit any "Intel is the one and only gaming processor" lollery that does its rounds.
Simply put a mere handful of broken or yet to be patched titles every show a significant FPS advantage that would make you want to spend $350 for a i7 to get roughly 3-5FPS more than a FX 8150 at $160 (needless to say the cost of a setup) Witcher 2, BF3, Skyrim, Metro, Dirt 3, any codemaster game barely and I mean barely show difference between AMD respective price point competitor chips, I do accept a minor group of games show around a 10% difference but those are all CPU dependent titles.
The other aspect that is hidden from many reviewers is MAX, MIN and AVG, they joy pony Intels max FPS at low and high res but hide the dismal fall off in AVG and MIN FPS notably higher res, this is odd as I don't fully understand why intel are affected more than AMD in this regard.