well a 470 is faster than a 460, but a 460 can overclock pretty high and almost reach a 470 stock in performance. however if you are really gonna overclock and overclocked and unlocked 470 can go beyond the performance of a oc 460
bacially either card will do almost all games on the market today at max setting at up to a 1920x1080 res... but if going for a higher res like 2560x1600 then i'd go 470