There is an OpenGL vsync bug in macOS Ventura 13.0 and 13.1 that affects vsync detection in PsychoPy. If you run “timeByFrame.py” or “timeByFramesEx.py” (see Demo->timing), you will see dropped frames and a mean win.frameIntervals that is incorrect (shows an odd bimodal distribution). For example, on a 60 Hz iMac monitor it shows a mean of 8.27 ms, whereas it should be ~16.67 ms.
OpenGL vsync detection works fine in macOS Monterey (tested on Intel and M1 Macs). Thus, best to avoid macOS Ventura when running PsychoPy experiments on a Mac until this bug is fixed (hopefully in macOS 13.2).