I've seen major slowdown of the kind i experience on menus on the darkmod also on retroarch and the root cause of that was using XWayland and was solved by compiling Wayland support in.
The 'xeyes test' (xeyes move if the xeyes can capture the mouse over the window being focused over is not Wayland) fails, so apparently the context is not x11, but the command line says things like:
----- Initializing OpenGL -----
Setup X display connection
Initializing OpenGL display
Using XFree86-VidModeExtension Version 2.2
Free86-VidModeExtension Activated at 1366x768
... (much later)
Fatal X Error:
Major opcode of failed request: 153
Minor opcode of failed request: 18
Serial number of failed request: 74
BadValue (integer parameter out of range for operation)
Couldn't exec autocommands.cfg - file does not exist.
Shutting down sound hardware
So it appears xeyes fails for another reason.
Edited by i30817, 06 February 2019 - 10:39 AM.