For basic powering of the board you just have to plug in 2 6 pin pci-e cables to any of the 6 spots on the edge of the board. I use the pair closest to the psu. You can use a single double plug cable for this. There is no 24 pin atx or 8 pin cpu for this board. the onda board has these but not Octo. if you are running cards without external power like gtx 1050's then you would plug in all 6 of the 6 pin pci-e on the board. For higher cards that have their own power connections, you just use the first 2 and the rest of the cables would be for powering the cards directly. If you are using a server psu a 12 port breakout board would be good. 2 for the motherboard and the rest of 8 cards. If the cards use double 8 pin or 8pin and 6 pin then just use a 8pin to dual 8pin splitter and you'll have no problems.