well I am splitting my vga cables. I figured that they can power 150w cards for the 8pin connector, so I used a splitter and with a undervolted 1070 or 1060, it seems to be working fine. cables aren't even warm to touch.
It took me a while to get all 6 gpu's recognized but I managed after many attempts! Now I'm tempted to try a 7th and 8th GPU using m.2 PCIE adapters like some of you guys, but how are you powering a 7th and 8th GPU? I'm using a EVGA 1200W power supply and it only has 6 VGA connectors/cables and I assume it's not a good idea to use a Y-splitter cable for the extra two GPU's. My 6-rig GPU is using about 735W as I'm limiting the power to 60% on MSI Afterburner.
Are you guys using a SATA-PCIE cable of some sort? Is that safe?