In my opinion claymore.
My Rig Reports with Version 9.8 247.x mhs with 8 Cards running @1175/2200 with wattman, autovoltage, at a total power draw from wall with 1150w wich gives me roundabout 30,x mhs/Card at ~100w/Card (Sapphire Nitro+ RX580 8GB Hynix)

But if someone knows a faster one please drop a line.