If you are using Linux and AMD Beta drivers, you will notice AMD Testing Use Only or Unsupported Hardware watermark at bottom right corner. No worries. Deleting it is easy!
1- Download this script.
2- Run it as superuser and reboot.
How to run the script as superuser? Open terminal, type sudo sh, don't press enter, and drag-drop the script file to terminal window, press enter.
Example: sudo sh '/home/username/Downloads/amd_remove_unsupported.sh'