Well... I think I'm going to sell my 13 gtx1070 (eating 130~150Watt each) and one of the rig-packs (MB+SSD+Processor+MEM+PSU)
and buy 5 Radeon VII instead, and then undervolt 'em (200~220Watt each) to have same 400 ethash for less energy -$

P.S.
Those 1070's already passed their ROI long time ago so I don't care about Radeon's ROI, only hashrate/energy effectiveness