Hi @zoed,
You can check yourself whether you’re actually dropping frames by opening the Coder window > Demos > timing > timeByFrames.py > hit Run from the Coder window. You just need to let this run, and you’ll be presented with two graphs. There’s more explanation on this here.
I would also recommend setting up your monitor in the Monitor Center. Find out how to do this here (even if it’s just the size of your screen it’s still good to input).
However, I see that you’re on a Mac, which might mean that you need to follow the guidance in this post, which is to add and allow PsychoPy access in the Input Monitoring and also Accessibility in Security and Privacy settings.
Hope these help!
Kim