After testing for 24hrs. Here are my results. Running stable, except for the 49 expired blocks in 24hours.

Hardware: 6 x rx570 4GB

Settings:
Cclock: 1300 (900mV)
Mclock: 2000 (900mV)
Intensity: 58
Double Threads: True
Version: 1.3
Pool: Nanopool

Undervolted all cards using Sapphire Trixx by -100mV

I'm getting 952 h/s per card and 5712 h/s on all cards using 700watts on the wall.