"AMD's Linux engineers ended up delaying the Catalyst
9.3 release so they could spend additional time tuning this driver,
since it will be the last release that supports the R300 through
R500 series as the support is being dropped. The significant
feature that was pushed back into the Catalyst 9.3 Linux driver is
improved Composite support. Catalyst 9.3 for Linux has improved
support for Composite via supporting redirected OpenGL rendering
under Compiz.
"Yes, that means for all of the Linux desktops out there running
Compiz or KWin4 or other compositing window managers, the rendering
is now a lot better. With the open-source drivers, redirected
direct rendering is possible when using DRI2 and the related work
such as kernel memory management, but the Catalyst driver does not
use the Direct Rendering Infrastructure 2. The proprietary NVIDIA
driver also uses its own infrastructure for dealing with redirected
OpenGL rendering. With OpenGL composite support, windows and their
contents should be displayed properly even when dragging around a
wobbly window on a multi-sided desktop."