Created attachment 86376 [details]
color-corruption.png

I also have this color corruption all over the place with Native/OpenGL backend
and Glamor. As well as huge slowness/laggyness, glxgears at:

$ ▶ glxgears 
Running synchronized to the vertical refresh.  The framerate should be
approximately the same as the monitor refresh rate.
237 frames in 5.0 seconds = 47.022 FPS
250 frames in 5.0 seconds = 49.853 FPS
234 frames in 5.0 seconds = 46.726 FPS
253 frames in 5.0 seconds = 50.592 FPS
234 frames in 5.0 seconds = 46.440 FPS
256 frames in 5.0 seconds = 51.165 FPS
236 frames in 5.0 seconds = 46.952 FPS

On Radeon HD7870.