guys, which models of power supplies are you using for powering 8 cards on this board? Need to buy power supplies that need no additional cable extenders or splitters to power on rx580
For 8 GPUs you can end up buying a very expensive 1600w or higher but dual psu would be cheaper.
I use 2 x corsair RM850x. It has 3 pcie cables and 6 connectors (150mm distance between connectors). Has 8 molex connectors for powering risers.
However, you should opt for any cheapest, quality gold rated power supply with 3 pcie cables or higher
Note: don't blindly go by pcie connector count. (look for the distance between the connectors) Many times the connectors are closely placed on the cable and you won't be able to use it on adjacent GPU.
Few other recommendations EVGA 1000 GQ, EVGA 850w or higher G2/G3 series