I would recomend the 4670 with your system as is. Yes it may get a bit restricted by the CPU but i had a PC with the same CPU as yours untill very recently and can tell you for a fact that the 3650 isnt bottlenecked bt the CPU. That does depend on the display and resolution though, what do you game at ?
More Ram and a CPU Overclock are definatly good sugestions , just wanted to clarify my last post i wasnt saying the Ram and overclock are not needed, they are, its just that you would be mad to get a 3650 and not a 4670. Even a 4650 if money is tight would be better than a 3650.
I game at 1024X768 or 1280X1024, depending upon the game. Though I might be getting a new monitor thats 1440X900. My games include Counter Strike:Source, Call of Duty 4, World In Conflict, Spore. I am looking forward to getting Sins of a solar empire and fallout3.
My PSU is some generic 450W one that came with the case. It's served me well for 3 1/2 years however I've never done any OCing. I'm sure I would need a new PSU with my new graphics card right?
Could you guys link me some good OC guides, I'm not too keen on it.