Hi there!

I bought on ebay pci-e cables that are 6p on one end (This plug into the breakout board of PSU) and 6p+2p on other end (this plug into your GPU or wherever you need them)

I am using 2 cables per GPU and never had any issue. But I did screw up when i connected only one cable to power my Octominer mining motherboard, and then the plug burned, now i am using 3 cables to power the motherboard.
I use 17 port breakout board from ebay, these work great for me, and the one with 12 port, i didn't like so much, i think the connectors on them are not as good as on 17 port.

If you don't mind the noise, powering 6 vegas (optimised, of course, not at default settings where they pull 300 watt each) is easy with this PSU. Now my rigs are 8 GPU, i just use 2 1200W PSU, one powering 4 vegas, another 4 vegas and a motherboard, and that works nice for me and PSU is not as noisy as working with 6 vegas.

if you connect 2 separate PCI-e cables for powering the Vega (actually, vega will not work with one cable, both must be plugged) you will not have issues with burned connectors or instability. My only fuckup was that, powering a mobo with only one cable, and that was on 12-port breakout board and the plug burned. I think it was the plug fault on breakout board, not the cable itself.

cheers! Smiley