At That Res. You Can Play Games On Medium Settings Bt With Limited Frams...20-28 FPS...And In Some Games More Than 30....Bt For Latest Games That Are Still Not Lunched You Have To Upgrade Your VGA...Other Spec. Is Good...
And About PSU So First Tell Which Brand Of PSU You Have??
So have you bought the system or is this a system which you're thinking of building ? If you bought this system, then I'd say as everyone else says, you'd be able to play today's games at medium settings or low settings. HD 4670 is a competitor of the 9600GT. Since they are quite much obsolete cards, I'd say games like GTA IV would run good, maybe 20-25 FPS on 1024X768 all on low, and maybe water quality and shadows on medium.
A 300W PSU ? Which brand is it ? Does it deliver at least 17A on it's +12V rails ? Then it's okay, a 300W PSU would be enough, but it won't hurt if you tell us which brand it is. Also, if you haven't bought the card, then I'd suggest getting something better.