Do you have the game maxed out in the settings for your resolution, and are you playing at the max resolution you can?
Check out Gomez Peer
on how to make your PC work for you. Referred by dark2099 please!
Mini Rig: Biostar TP67XE / i5 2500k / Corsair H55 / 2x4GB PNY / XFX 7770 / Corsair CX500M / Win 8 64 bit / Thermaltake V9 Blackwidow