I run 3 TV's and have a 7950 BE and I have not had any issues with WOW or any of the main stream games I play. But its overclocked to compete with a 7970. I bet a 670 could do just fine with what you want. I can play MOH on max setting and not even break a sweat with my setup, and that is on all 3 screens. I don't know what FPS I get, but I bet its over 40. I can never see flicker or choppy play. FYI Don't buy too big of monitors or your neck will hurt during long sessions. Having your start button 96 inches away form your time and icon box is not ideal. I would not go over 37 inches if I could do it all over again. Oh and make sure the Bezels are small. Once your in the game you don't notice the lines, but if your not playing, it will annoy you.