Works for Windows 7, Windows 8, Windows 8.1 and Windows 10.
To fix your display:
Write down the resolution and display frequency your currently running at
- Start -> Run -> regedit
- Goto HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Video
- Select the subkey that represents the video card you are currently using.
For an example on my machine there were 3 sub keys under HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Video . We’re looking for the key that contains sub keys named 0000,1111 and video. The sub key with the ton of entries is the folder you want to be working with.
In my example {DD0F636C-AA03-420D-B43A-B3EC8A0BCA11}
- Backup the 0000 and 1111 keys.
- Select the 0000 sub key and search for your HDMIs resolution. In my example its 1920×1080.
So search for the entry DALR6 DFP1920x1080x0x59
- Edit the key that matches your resolution and change everything to zeroes.
- Click Ok and then edit the corresponding key in the 0001 sub key. Change that one to all zeros as well.
- Go back to your desktop and change your monitor resolution and then change it back to 1920×1080
The underscan should be gone now! Can confirm that this works with Radeon HD mobile 4200 video cards.
