https://bugs.freedesktop.org/show_bug.cgi?id=88758
--- Comment #18 from Lorenzo Bona lorenz.bona@gmail.com --- Reverting this commit
http://cgit.freedesktop.org/mesa/mesa/commit/src/gallium/drivers/radeon/r600...
helps a little bit.
But it's not as fluid as on 3.16rc6 kernel.