I mean dual PSU with combined total 2050watts. I am still having some issues with the secondary PSU shutting off under heavy load, the highest GPU power limit i can hit without my PSU shutting off with this setup is ~105% or 275w x 4. It is an older 850w unit and must be pulling to much from a single rail. On a single 1200w psu i could run tri sli to 130% (325w) no issues however quad SLI would crash at any power limit even well within what it could handle I'm guessing just to many things pulling amps at the same time caused it to trip out. I am planning to run 3 GPUs + system off 1 psu and 1 gpu off the secondary when I get around to it. Yeah i would not expect a 4x pcie lane to effect folding or mining at all, gaming in SLI uses the bus much more heavily even single GPU barely touches the bus in games. My CPU uses about 210w with HT off and ~240w with it on in workloads, 170w tops in gaming.