I'm quite surprised. Didn't know Antec had a PSU calculator.
Even more so that my setup can run SLI with 2 GTX 460's using my current power supply the Antec 650 Earthwatts PSU with plenty of headroom. I know in order to run SLI i'll need 4 6 pin connectors to run 2 GTX 460's and the Antec 650 only has 3 but i got cables that convert other connectors into a 6 pins so it's all good. Guess it all depends on comp setup for power usage.
And here i thought i'd have to spend 100+ dollars to buy another power supply to get SLI working. Trusty Antec is all i gotta say.