In CPU limited games Sandy Bridge has shown real benefits for me coming from a 4.2Ghz Phenom II quad and a 4GHz 1090T.
GTA IV, Oblivion/Morrowind.Skyrim etc all play smoothly now at 1080p with much higher frames whereas previously smooth frames where hard to come by.
Your card is more than adequate and I definitely recommend the intel setup, not just for the game in question but for improvements in a plethora of other titles.
Let us know how you get on mate
