WoW is very very CPU bound game, if u want to run wow on ultra even GTX 560 is enough, but the main problem is the CPU, get intel 3570K/4670K. There's some people who got fx-6300 processor and gtx 660 card and wow is still at 20fps in raids because it cant utilize multicore technology, sure they say that "we got multicore support" but in reality it's almost non-existant.