Just to add to this: I experienced the same problem (Ubuntu 16.04, psychopy 1.83.04) and solved it by turning off “Sync to VBlank” in my NVIDIA settings app. The advantage is that I can send the code to collaborators without deleting the waitBlanking. Of course, you have to be sure that you really want to disable vsync system-wide, but unless you’re a gamer, it shouldn’t really affect any activities.