Well i looked at the charts on Tomshardware and it seems to me thats its a big improvement its almost double the frame rates in almost all the tests.
By the way i play games like Far Cry, Crysis, Call Of Duty 4, Dirt, Half Life 2, Bioshock, Need For Speed Carbon, Need For Speed Pro Street, and Call of Juarez. Theres more but that gives you an idea lol. Plan on getting Far Cry 2 and Assassins Creed when they come out. Plus i play my games at 1680x1050 resolution.
Thanks