That's correct, you need to patch the driver with the pixel patcher to bypass the signature check with a modded bios. Once the card shows up in Device Manager without errors, you can overclock and undervot it using Afterburner before starting the miner. Somewhere around 1150 MHz for the core clock and 2075 MHz for the memory clock with a -98 mV undervolt should get you to 28 MH/s.
Hi, the only driver install that I have done is to install the latest AMD driver a couple of days ago when building the rig. After this I had modded the card and the patcher works so that I can see the card but still no change in the hash rate. Do I need to reinstall the drivers for each card when I mod it?
If you have cards with a modded Bios, you need to use the pixel patcher any time there is a driver update, after adding a card or changing the Bios. If the card is still not recognized in Device Manager, uninstall the drivers in safe mode using DDU, reinstall the driver and apply the pixel patcher.