ATI underscan and overscan without CCC

Open regedit and go to:

In there, there’ll be some keys looking like this:

Look for keys that begin with DALR6 DFPXXXXxYYYYx0xFF

XXXX= Horizontal resolution
YYYY= Vertical resolution
FF= Display frequency

Click on the key matching the screen resolution and frequency you want to remove the borders of.

A lot of the key will consist of “00”, but there’ll be a few non-00 entries. Change all of these to 00.

There may be two subfolders, 0000 and 0001, containing mirrors of the same keys. When you change a key in one subfolder, it will also change in the other.