What is the reason ?
I'm trying to avoid using a third PSU because I lack enough plugs/cables especially when I'm only using 60% of the wattage.
My second EVGA platinum PSU had 2 unused CPU ports, if those are a viable option to power my GTX cards then I'd rather use those instead of trying to run 3 PSU's.
From what I've read the CPU ports have more than enough power to run 2 GTX cards each, that'll put me at 8 cards on this PSU with 5 on the other maxing me out at 13. On top of that I'll be at about 80% usage.