I'm using Claymore in Windows 8.1 with 2 1070's and 2 1060's - all are core underclocked to -100 and memory overclocked to +750 using MSI afterburner..
I'm using an 850W PSU and the whole system is running at around 600W.
So there are a few differences to your system but mine is very stable, hashing at about 107mh/s.
1070 should be doing about ( from what i read and watched ) 130 watts per card