Use that to calculate your wattage requirement and also check manufacturer specs. The minimum for the gtx 570 is a 550W PSU.
It should be good for your system plus some overclocking.
The minimum recommended for a GTX570 is a 550W PSU, the one you have selected should be plenty unless you plan to SLI that with another GTX570 later. In that case you will want something around 800-850W.
Do you want to do SLI/CF or using more than 1 card in the future? If not then that Corsair 650W is enough for your need.
If you want to objectively, accurately and scientifically determine what PSU power is required for your Vid card and PC in both watts and 12v rail amps., the forum Utility link below will show you how easy it is to calculate this information and objectively determine which PSUs are quality built, reliable PSUs that can meet your needs. Be advised that the available 12v rail amps. is just as important as the total PSU wattage. You need both to be correct.