I'm running on a late 2013 15" Retina MacBook Pro (the top-end model with discrete Nvidia GeForce 750M graphics) and I've found that the game tends to have some difficulty running at a good frame rate at anything but the lowest graphics, lowest resolution, and no vsync. If your computer is older (or about the same age but with lower-end graphics hardware) then it might be a challenge to get the game running acceptably.
One thing I did that may help for you is, I created a new user profile in the "Users & Groups" pane of the system preferences, and I use that profile exclusively for FS, to ensure that nothing else is running while I play (and the fast user switching feature means it only takes a few seconds to switch between that and my normal setup). I also use a resolution changer app called RDM that lets me set the display resolution to 1024×768 (not HiDPI mode), which seems to help somewhat as well.
Interestingly, I do have a more or less completely clean and fresh Windows 10 partition on this computer, and the performance on there is about the same as it is on macOS for me. You mileage may vary.