Radeon HD 4xxx? Actually, you just need to install legacy drivers, that's your only problem here, not AMD.
"Since Catalyst 12.4, AMD has separated its development for Radeon HD 2xxx, 3xxx and 4xxx cards into the
legacy Catalyst driver. For Radeon HD 5xxx and newer, there is the regular Catalyst driver. Regardless of the driver you need, you will also need the Catalyst utilities."
https://wiki.archlinux.org/index.php/AMD_Catalyst
All my high-end, up-to-date hardware is AMD nowadays. And I must say their Linux support has increased to a point I have no more video issues at all.