No bios trick are needed, it's just memory timing.
I use teamredminer on HiveOS + amdmemtweak to apply timing and it's pretty cool.
https://github.com/todxx/teamredminer (they have tweaking guide)
I have a steady 50 MH/s (I can push to 52-53, but the extra watts are not efficient)
I also have a Vega 56 GPU but I'm looking forward to sell the card because of energy consumption but I heard this card can do 120watt but no luck yet, can you share your power consumption after memory tweak? Thanks 👍👍