Quote from: timeshifter on January 21, 2018, 07:37:08 AM

I'm not afraid to start a power supply by shorting the two pins together with a paper clip, done it before for testing. But what about the sequence of power being applied. The power supply will light up the graphics cards with the two 8 pin connectors and power would be supplied to the "risers", in this case additional PCIe connectors that connect to the motherboard. I'm kinda worried that 1/2 of the cards and part of the mb will receive power before the rest of the system.

The way I would structure the power supplies is have one supply all the PCIe external power connectors on the GPUs and the other supply all the mobo connectors. As long as you turn on the GPU PSU first and turn it off last (or just leave it one - the cards draw hardly any power while off) you won't have any problems. Trying to supply half the mobo and GPUs with 1 PSU and the other half with a 2nd sounds nightmarish.