I have this model (ASUS STRIX RX 570 )
1500->2000 timings
1300 -> 1100 gpu clock
1900 memory clock
I get stable 27.6MH/s with roughly 116W per card

On top of this I undervolt 50-75mv per card and can get to 104W per card stable. (100% fan)

edit: just to add here are my settings in polaris.  Note this is just what i've tested and done - it may or may not work for others but it does for me.  If you find improvements that you've tested would appreciate replying and sharing.


Hope to help