Many AMD/ATI boards (but not all) are supported by xorg-x11, at least for the 2D accelerated features. The 3D support is provided either by xorg-x11, or by AMD's closed source drivers. AMD's closed source driver was available since the R200 GPUs, but support for current versions of X11 is limited. The last version of the Catalyst drivers fglrx had support only for R600 (since HD5000) and newer GPUs and X.org server 1.17. Older GPUs will use the mature open source xorg-x11 driver. For newer GPUs since GCN (Graphics Core Next) Generation 1.1 (Southern Islands and newer) drivers are provided as open source AMDGPU and closed source AMDGPU-PRO. Both have excellent 2D and 3D accelerated performance.