Underscan problems with certain games and ATI Catalyst Control Center

So, I recently installed Windows 8 on a new SSD drive and re-installed my steam games from the backups I had made, and to my horror most of them did not take the whole screen in full screen mode: there were big back borders on each sides of the screen. I remember that I had the problems before in Vista but only when games were running using directx 10. I did not know why and did not bother as most games at the time could run using directx 9.

For the information here is my setup:
Philips LCD sreen with overscan turned off => HDMI cable => DVI adapter => DVI port of the graphic card.

My windows desktop resolution is set at 1920x1080@ 60Hz
And overscan is set to 0% in ATI's Catalyst Control Center (CCC)

This configuration worked perfectly and filled the entire screen in Windows. In half my games, using the same resolution as the desktop would fix any border problem but in the other half there was a big black border.

Turning on the overscan on the screen while these games were running only diminish slightly the black borders. And it made the image slightly blurry.

So I searched on the web saw that many people had similar problems, there were many solution recipes but the first few I tried failed solve the problem for me.

I finally stumbled on this wiki article which made me understand the problem: each resolution AND framerate COMBINATIONS have their own settings in ATI catalyst control center. You can only see the configuration for the combinations which is currently selected in Windows Desktop. In some games you can't select the frequency in the settings and they probably chose 50Hz randomly.

So my current configurations was:
1920x1080@ 60Hz : The configs I had carefully selected in CCC.
1920x1080@ 50Hz: Bullshit configurations I had never seen in CCC.

The solution was to go in the advanced settings for my screen in Windows, switch to 50Hz. Then open CCC, (I could see that the overscan was at its default value), ajust all the settings (putting the overscan at 0).
Then I changed back my windows resolution to 60Hz but when I would start those 50Hz games, they would take the full screen correctly.