I have recently switched to an AMD graphics card, and with it have installed the latest stable-release FGLRX drivers, on my Ubuntu 12.04 system.
The drivers' default settings for my desktop size do not adequately fill my 27" monitor's resolution of 1920x1080 -- leaving approximately 1-inch black borders on all sides. This makes it necessary to increase the overscan setting in the Catalyst program to 0%, in order to fully occupy the given space.
This default setting is true not only on Ubuntu, but on the Windows 7 equivalent as well.
While the Windows version of Catalyst preserves adjustments to the overscan setting upon reboot, Ubuntu's resets them. No matter whether performed in administrative mode or in user mode, any changes to the setting revert to the default.
It is inconvenient to have to manually reset the overscan every time. Hopefully this will be resolved in coming updates.
Additionally, whether related, these black borders are also present on the motherboard splash screen, as well as the GRUB boot-loading screen.
Regardless, thank you AMD team for your attention and efforts toward Linux support thus far. We hope it will continue.
(This issue was mentioned in an older thread from last year, Overscan settings lost on reboot..)
Ubuntu 12.04.3, 64-bit
Unity Desktop Environment (vanilla)
Asus M4A78LT-M LE Motherboard
Asus BIOS Version 0803
AMD Athlon II X4 645, 3.10 GHz
AMD Radeon HD 6790
Catalyst Control Center Version 2.18
ATI/AMD Proprietary FGLRX Graphics Driver (Post-Release Updates)