ATI(or I should say AMD) put the overscan settings in an obscure place. If there is a bad UI design contest, this definitely belongs to the top 10. The switch is so hard to find that we have to attached screen to show the location. Someone really need to yell at their software developer to get them to wake up. To configure overscan/underscan to fix black border when you use HDMI to connect to your monitor, do the following:
1. Open Catalyst Control Center.
2. Goto Graphics and Display and below you will see screen with tiny triangle, click on the triangle and you will see ‘Configure’ menu. (See image 1)
3. In the next screen, click on Scaling Options tag.(See image 2)
4. Adjust underscan/overscan using the slider.(See image 3)