from what i've read etc not really, only unless your running more then 4gig ram and even then the gains are questionable.

once you start clocking it and get that gpu clocked it should really start flying, though a word of warning about the gt's i've read alot of them will only run at a certain fan speed, so when playing games if it gets to a certain point and then crashes you may need to install a fan controler, to help keep it cool. just a heads up incase you panic thinkin the cards fucked lol