2x MSI RX480 8GB, Getting 80-90H/s

You can push those each up to ~52 ish, I have the same card, you need ~3 modifications to the Bios.
use the Polaris bios editior to
Change memory strap: to 777000000000000022339D00CE516A3D9055111230CB4409004AE600740114206A8900A00200312
0150F292F94273116
then bump the memory speed to 2200
and change the mem voltage from 975 to like 1025-1050 (this is needed for stability i found at 975 it crashes every few hours)
massive your millage may very but all the cool kids are doing it so, gl!