you can read this~
http://www.tomshardware.com/reviews/best-graphics-card-radeon-hd-6990-geforce-gtx-590,2912-7.html
Discrete: 6600 GT, 6800LE, 6800 XT, 7300 GT (DDR2), 8500 GT, 9400 GT
Go (mobile): 7600 (128-bit)
Discrete: 9800 XT, X700 PRO, X800 GT, X800 SE, X1300 XT, X1600 PRO, HD 2400...