I have a Q660 at stock, and a gtx 650 Ti (2GB Windforce). I can get max settings on most games (1680x1050) but in some I get low fps.(Splinter Cell Blacklist to be specific).I think it's a cpu issue, will overclocking help? Windows 8 Pro, get 50c temp at idles, but in Australian Summer, so that is probably affecting it.
