Please include a minimal reproducible example when you ask a question.

For now I have made one with your code. https://editor.p5js.org/Metabyte/sketches/l10Cctomw

There doesn't seem to be any stutters when running this version, so the system you must be running on has to have someone else making the mainloop busy.

Try running this sketch on another machine and see if the stutters still continue.