https://bugs.freedesktop.org/show_bug.cgi?id=100742
--- Comment #1 from Felix Hellmann privat@cirk2.de --- I can observe the same behaviour. Setting power_dpm_force_performance_level to high reduces ans smoothes out the StreamVr Compositor frame timings. Even when no "real" app is running (so just the basic space you get when launching)
Arch Linux RX 480 i7 3770k 4.11.7-1-ck Mesa git from 2017-07-03