For the Bios mod I use the Polaris Bios Editor v1.6.2 'one click timing patch'. It automatically detects each memory type and adjusts the 1750 MHz and up straps with the bundled performance straps. PBE v1.6.3 and up adjusts the straps from 1500 MHz and up, but the 1750 MHz straps are more stable. It works great with all my RX 480/570/580 cards. 28.5-31 MH/s ETH + 740-900 MH/s DCR.

https://github.com/jaschaknack/PolarisBiosEditor/tree/9ec64066eecdb55ac86da7bc82181eaab2161d51