Guys, I just got my 6 Vega 56 cards... I wanted to power them with an EVGA 1600 G2 but I just don't have enough VGA power connectors! Do I really have to connect 2x 8-pin per GPU? Is that needed for mining?
Go to eBay, get the splitters, like this one:
https://www.ebay.com/itm/1-Pc-PCI-E-6-Pin-Femal-To-Dual-8-Pin-6-2-Pin-Card-Power-Adapter-Cable-PCIE-PCI/222615689892?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649They work well. I've used them on 1080 Ti and Vega (but I undervolt, I don't go crazy with TDP +120 or anything like that).
But if I were you, I think would think about a server PSU, maybe the DPS-2000 or DPS-2500 and a price-technology.com breakout board, 6-pin cables to PCIe risers, 6-pin cables to (2) 6+2 pin splitters for GPU. You'll need a pico psu as well and a 240v outlet OR a step-up transformer (search "ELC step up transformer" on eBay).
All of that is less that the EVGA 1600 PSU. Not that I have anything against EVGA - that's a solid PSU.
if you undervolt it should be ok but not too safe 2x8pin cable can do 360w can go bit higher but check if it not getting hot
what you could do is add a wire from a molex cable , it s what i do, i manually connect a wire from the molex +12V and plug it in on 1 of the 3 +12V, and put some tape so the wire cannot get out by accident
problem with vega even if you undervolt to 150w it has a lot of pics what use more than 150w
i tried 2x vega on a 750w psu when it average use less than 550w , time to time the psu was shuting down (so get up to 700w?)
i put 3x vega on a 850w (there are only 4x 8pin connector) i made 2 extra 8pin my self used bridge + all molex connectors better use to much wires than too less