Definitely mod the bios for them. Just make sure to save the original bios for each card by serial number. Just go to Techpowerup for a couple tools you'll need. GPU-Z and AMD AMDVBFlash. They have a lot of info too. Also, search Polaris Bios Editor Pro. Sells software that mods bios in one click. Or you can take a chance with looking up modded bios. Also might need to patch drivers after Bios mod if running Windows.