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