Well my psu is 400watt (unbranded) and here is it's details
+5v +3.3v +12v -5v -12v +5vsb
26.0a 14.0a 12.0a - 0.5a 2.0a
I have c2d e4500 wid 2 gb ddr2 ram.
Can my psu handle ati 4670. I think it can't handle 9600gt but if it can't handle this card then my hope of playing gta4 may be over. And i can't upgrade my rig! ! ! except the video card.
Now, i'm using 8400gs.
Lower resolutions aren't "more" cpu bound they are simply less video card bound. You will never get higher frame rates by increasing resolution no matter your set-up. This is a HD4670 we are talking about. it's fine to pair with a mid-range core2duo. Overclocking that chip is a great idea though. Should easily get up to at least 3 ghz on stock cooling. It would definitely help in processor intensive games like GTA4 and Crysis but either way GTA4 should be more than playable at moderate settings.