THIS GUIDE IS UNDER INITIAL CONSTRUCTION
AMDGPU-PRO is AMD's open source AMDGPU driver with a proprietary overlay. What this means is that AMD's "proprietary" driver will be based on its open source driver!
AMDGPU is AMD's open source graphics driver for the latest AMD Radeon graphics cards. It is a compliment to the open source Radeon driver, which works with graphics cards not supported by AMDGPU. AMDGPU is under intense development in coordination with the larger open source community. AMDGPU supports a growing number of cards, but will not be available for pre-GCN (Graphics Core Next) architecture cards. This means that as development progresses, some select cards as far back as HD 7000 cards will be supported. No HD 6000 or prior cards will be supported.
Support for AMDGPU-PRO begins experimentally with Ubuntu 16.04 -- which, incidentally, does not support fglrx -- and is fully supported starting with 16.10.
At the time of writing, the cards supported may include many of those listed in AMD's list of cards supported by AMDGPU-PRO here.
This guide shows you how to use the AMDGPU-PRO driver for some ATI/AMD graphics cards and APUs.
RadeonDriver - The Wiki page for the open source Radeon driver.
BinaryDriverHowto/AMD - The Wiki page for the proprietary AMD/ATI driver "fglrx" which also offers 3D acceleration, and works on newer cards than the "radeon" driver. Since it's closed-source, only AMD can work on it and give efficient support, and the open-source community can generally not help you with problems.