Latest bisect result so far: Fast mesa version: 17.2.8 (2017 december 22) Slow mesa version: 18.0.5 (2018 june 3) The change that slows the system is between the two. The strace outputs are generally the same as before so it is not worth sharing but I have them and they differ the same way as I told above - more GEM_CREATE ioctl calls in the slow ver.