I got 9x RX 580 undervalted to 900mw and most pulls 150W for each GPU. I mostly mine cryptonight heavy or Cryptonight7 which are not too GPU intensive. Total pull is around 1150-1180W. It runs OK, but sometimes it hangs at boot or randomly restarts and hangs at boot. I suspect it is the PSU, but wanted to hear second opinion. System used for mining and PSU is Lepa 1600W Gold rated PSU. I am thinking to drop it to 8GPU and add 2 more GPU along with 750W psu. so 8 run on 1600W and 4 run on 750W.