I had this on occasion but couldn't reproduce it reliably:
Go to:
http://global.burton.com/on/demandware.store/Sites-Burton_GLOBAL-Site/default/Team-Riders
and move the cursor over the faces.
You will see many (toooo many) errors like the one below in the journal:
Oct 11 23:20:38 mainland kernel: [drm:radeon_uvd_cs_msg] *ERROR* No more free
UVD handles!
Oct 11 23:20:38 mainland kernel: [drm:radeon_cs_ib_chunk] *ERROR* Invalid
command stream !
Linux mainland 3.16.4-1-ARCH #1 SMP PREEMPT Mon Oct 6 08:22:27 CEST 2014 x86_64
GNU/Linux
glxinfo | grep -i opengl
OpenGL vendor string: X.Org
OpenGL renderer string: Gallium 0.4 on AMD BARTS
OpenGL core profile version string: 3.3 (Core Profile) Mesa 10.3.0
OpenGL core profile shading language version string: 3.30
OpenGL core profile context flags: (none)
OpenGL core profile profile mask: core profile
OpenGL core profile extensions:
OpenGL version string: 3.0 Mesa 10.3.0
OpenGL shading language version string: 1.30
OpenGL context flags: (none)
OpenGL extensions:
OpenGL ES profile version string: OpenGL ES 3.0 Mesa 10.3.0
OpenGL ES profile shading language version string: OpenGL ES GLSL ES 3.0
OpenGL ES profile extensions:
The dmesg is useless cause the error filled everything.