Hello.
I have 7 MSI GTX 1060 3G on Biostar TB250 and all 7 cards works fine (+800 MHZ SAMSUNG memory overclock) 170 MH/S (>24.2MH/S) at 620W power using Claymore 10 on Win 10 PRO/1703.
Have you ever try dual mining with ETH, maybe you can get more profit.