Here, now you can do the math..
http://support.asus.com/PowerSupplyCalculator/PSCalculator.aspx?SLanguage=en-us
Folding@Home
http://support.asus.com/PowerSupplyCalculator/PSCalculator.aspx?SLanguage=en-us
Folding@Home
It's a different model but I would suspect that there are many similarities probably including the rail layout. Seasonic makes a quality PSU so I don't believe you will have any problem using you current Seasonic 650.Now on the previous page, you saw that Seasonic advertises this PSU as having four 12V rails. You'll notice in these load tests that I only specify a load on 12V1 and 12V2. This is because I could not find any proof that this PSU had more than two 12V rails; at the most three. And I found that even if there were three 12V rails, there is no OCP (over-current protection) or any circuitry in place that disrupts continuity between the multiple "rails." We'll discuss this further during the autopsy.