my rx 580 8GB didn't get pass 30MH/s not sure why, only can get around 29.8Mhz
command i use -amd -rxboost 30 -clKernel 1 -prate 0.12 -cvddc 825 -mvddc 850
same result with memory overclock to 2250Mhz
using latest pm miner with 20.11.1 driver
What is you clock speed on your gpu core?