I currently have a Cooler Master GX 650 W psu powering 2 MSI Twinfrozr 7850 just factory overclocked in Crossfire configuration.
When I'm in a game the PSU gets loud (FAN) and hot to where I'm like sweating near the computer. Then temperatures never seem to get too hot on the Cards or CPU (3570k @ 4.2 ghz). I'm thinking this PSU just sucks for any CF/SLI config. From all the PSU calculators this should supply enough power to my entire computer and not be a problem.