It was due to using and HDMI input on the monitor I think and not being able to adjust the overscan since Catalyst Control Center for the driver needed wasn't compatible with Windows 10, but whatever the root cause was, this reg hack fixed it for me after making the change and rebooting. I finally found a post on another forum with someone having the issue with another brand computer, but a 3000 series ATI card. It wasn't horrible, but there were black borders and very slightly blurry.
I had to use a legacy driver and Catalyst Control Center to get it to work in Windows 8 (unsupported) and all was great but once I upgraded to Windows 10, the graphics were not right. I had a similar issue with my ATI HD 3450 graphics card.
