I use my Toshiba 55G300U 55" HDTV as a second monitor with my HD5770 via HDMI. Recently, it started only using 85% of the screen leaving a two inch or so black border around the image, even when picture size was set to native in the TV's menu. I posted here and was told I could fix it by going into Catalyst Control Center, enabling GPU scaling, and adjusting it to 0%, which fixed the problem.
The problem is that I have to do this every time my computer restarts. I have tried toggling all of the options in CCC that seemed relevant, but nothing helps. All of my other settings in CCC stay to what I set them to except for this one. I have updated to 10.9, but that did not help.
I feel your pain buddy...i got so pizzt with 10.9 that andup being banned from amd forum( blow a fuse ),long story short try this hot fix,works for me :http://support.amd.com/us/kbarticles/Pages/ATICatalyst109Hotfix.aspx