Well my 600$ build w/ the 6850 and Rana would give you the best graphical performance. Sure sure, the 445/450 isn't a quad or a Phenom. But as far as gaming goes, its more GPU than CPU. The only time the CPU has effects are in games that suck at coding (GTA 4) or RTS (SC2). Other than that it would run fine. The 6850 won't run the games you want at max, but it'll do the job better than the 5770 and 460. Also run at a better quality. (The 6850 has HDMI so, most LCDs use that anyway).