https://bugs.freedesktop.org/show_bug.cgi?id=101769
--- Comment #2 from Matias N. Goldberg dark_sylinc@yahoo.com.ar --- Bah, nevermind. Either my bug is not related or it gets fixed the same way.
Updating kernel from 4.11.6 to 4.12.10 seems to have solved all the weird performance issues.