Originally Posted by Raggz

Hard to say but 15-20+ fps depending on the game and your system (CPU, Ram speed and possible bottlenecks). There are many tests on google of GTX480 vs GTX 580. Do a search and check them out

Just remember that these cards require a minimum 750w PSU with 42A on the +12v rail or you will probably face freezes, BSODS and reboots. I know some sites, including Nvidia, claims minimum 600w but i really recommend 750w if you don't want headaches. Second, if you do need a new PSU, DON'T go for a cheap one. Buy a known and good brand. You won't regret it.