AM3 Athlon II 620 X4
I get reasonable performance gaming wise but I think it's time for a new GPU I am thinking of buying an ATI 5970 will I see the differance? and this new card should last a couple of years till i upgrade my sysyem again tell me what you think and maybe any other changes i will need (i am upgrading my PSU for a 750w)I am also thinking of overclocking but dont know how !!
Yea the 5970 is the best gaming card on the market, but it's also very expensive. Given the older PC it would go into, I think it's a bit of overkill. It would, however, be adequet on it's own to play games at high settings for a few years from now and if you upgrade your whole system it'll fit right in on a high end rig. However, you don't mention if you're using DDR2 or DDR3, and there could be some bottlenecking there as well as on the CPU as shadow pointed out. I have a 5850 and I highly recomend it, I've been able to play every game at max settings 1950x1080 resolution. Even crysis is very playable at ultra, tho the draw distance on objects is fairly short so I prefer the High setting at which point it's a steady 50fps and really it looks fantastic. If you have a little extra cash to burn you might want the 5870 as it's a slightly better version than the 5850.
Oh and the 5970 is something like 11" long, so only the biggest tower cases can even hold one in. Definitely need to consider that.