https://bugs.freedesktop.org/show_bug.cgi?id=88227
--- Comment #10 from Marek Olšák maraeo@gmail.com --- James, can you increase the size of cache manually and see what works better? There is only one formula in radeon_drm_winsys.c:676, so it should be trivial.
Also please how much VRAM and GTT do you have?