Hi guys
Would it be okay to run 3 1080 ti and 4 1070 with only 1600w PSU (supernova P2)?
it looks like it come out to about 1506w TDP combined including other components
Depends on the models but most aftermarket 1080 Ti's are using 300 watts and 1070s pulling 180. That puts you at 1620 wats max plus 70-100 watts for the rest of the components so ~1700.
I'd not advise going above 80-90% on any PSU, not even on top quality monsters like EVGA 1600W P2.
So I would set the power limit on all cards to ~about 80-85%.