I was assuming his psu didn't have any 6-pins coming from the PSU to support a beefier gpu and he didn't want to upgrade so I recommended the 6670 (sure it can max it out, but not at good FPS LOL idk some people just don't care about frame rate if it's over 30) for potential budget reasons...plus AMD says minimum 400W for 7750 but hey, if anything, the 7000 series consumes less power, right?
Then again, we've been recommending all these cards without even mentioning resolution. /hindsight
OP should have no problem getting a 1GB+ vram card, but the question is, how much horsepower will be required to get good FPS on 25-man raids at max settings at OP's res?
And since when does WoW use DX11?!?! :O
I remember running that at max on a 9800GTX