Nvidia 425m vs Ati 6630?

Hi, so I'm deciding between two computers. I am a casual gamer so I don't need it to play every game flawlessly but I want it at medium settings. I'm also a student. So I'm deciding between the sony vaio c series with 2.3 core 2 duo sandy bridge 4gigs ram and ati 6630 1 gig or sony f series 2010 model that has the older intel quad core i7 with 1.7 ghz - 2.93 with turbo boost. 4 gigs ram an an nvidia 425m 1 gig. They only difference I care about is battery life cuss the F series only gets 2 hours while the C series gets 5.5 hours. I'm willing to sacrafice the battery if the C series wont be good for games. So which one is better for games and also how do you think they would run games