Wow !!?! So I presume I use ATIwin , save my original bios , run it through PBE , it produces a modded bios , use ATIwin to flash the modded one ?
Yes. Just give the modded Bios a new name when saving it so you don't overwrite the original. You also need to run Atiwinflash as an administrator. I would suggest removing all the other cards from the PCI-E slots and leaving just the card you want to flash to make sure it's the right card. Wait for Atiwinflash to finish and only reboot when it says you can.
With most cards, you also may need to use the pixel patcher after modding the Bios to bypass the signature check when using a modded Bios.
https://www.monitortests.com/forum/Thread-AMD-ATI-Pixel-Clock-Patcher