Just look at your GFX card (s), nothing else matters, unless you are building a server, water cooling w/ multiple pumps or other very rare efforts.
http://www.geforce.com/hardware/desktop-gpus/geforce-gt...
Thermal and Power Specs
Maximum GPU Temperature (in C) = 97 C
Maximum Graphics Card Power (W) = 244 W
Minimum System Power Requirement (W) = 600 W
Supplementary Power Connectors = One 6-pin and One 8-pin