645 is better than the 650 according to display im telling u
and i can run crysis 2 on ultra with it not lying
i got it with my alienware for $699. pretty good price
read this :
http://www.game-debate.com/gpu/index.php?gid=1724&gid2=1149&compare=geforce-gt-645-oem-vs-geforce-gtx-650-1gb