Let's see..
well, a
system equipped with
ProcessorIntel Core i7-3960X @ 4.3GHz
MotherboardEVGA X79 SLI
Disk DrivesSamsung 470 (256GB)
MemoryG.Skill Ripjaws DDR3-1867 4 x 4GB (8-10-9-26)
and
GTX 770
only consume
374 watt for total power consumption while gaming..
and 383 watt while stressing with Furmark for
total power consumption
So, any 500w+ good psu from well known brand (seasonic, corsair, antec, fsp, etc) more than enough to run your system...
if your psu is a good quality psu, then your 650w psu is more than you need..