post #21 of 21
Connect the green "Power On" wires" of the PSUs together. Connect their grounds together. Have one PSU run all or most of the video cards, have the other PSU run everything else.

But before you do any of that, check the power draw of your system with a Kill-A-Watt because I doubt you'll ever need even 1200W, but if you do, run each PSU from a separate circuit breaker.