I have the same problem and I fiddled with the CCC and found that if i unchecked the box that said "enable GPU scaling" under the "My digital flat panels" and then goto the "properties digital flat panels" and uncheck the "Enable GPU scaling" box. The game still started in windowed mode but when i changed it to full screen and hit apply I did'nt get the black boarders anymore.

Hope this helps

NinjaVik