I've never tested on Mac or received feedback from Mac users. The game is written in Python using the pygame framework. The engine is my own. It should run at a constant 30fps with minimal CPU and GPU usage and never drop below 30fps. There can be a slight variance because of the inaccuracy of timers in Windows, and your problem can be similar on Mac. There is an option to change from the fast clock to an accurate clock. This might fix your problem.