It depends on the card and memory maker. What cards are you interested in?
Generally it's pretty straight forward:
1) copy tighter straps for the top memory ranges (from 1500 -> 1750 to 2000 depending on the memory)
2) set fixed voltages(not default offsets) lowering the highest  to below 950mv. (I don't look to get the every bit of juice from my setup, so my bios top core limits are around 1180MHz@ 923mv)

You can look for ready to use bioses for various cards, it would be probably easier to find if you look here: https://forum.ethereum.org