The 9650 is a lot like the 9600, but a bit faster. It's a rebadged 9600XT. According to Apple's own website, both the 9600XT and the 9650 have a 1.6 billion pixel/second fill rate, while the 9600 has a 1.3 billion pixel/second fill rate. More importantly, the 9600XT and 9650 have a 600 MHz memory clock, resulting in 50% higher memory bandwidth than the plain 9600, which has a 400 MHz memory clock.
It's not high end by any means but it'll suffice for gaming and it's absolutely fine for any 2D stuff you want to throw at it. And yes it'll run a Dell flat panel.