Taking notes in math courses in Vim on a netbook (remember those?) is what made me switch to Emacs! I tried taking notes both in LaTeX and in Markdown with syntax highlighting for embedded LaTeX math formulas, and Vim just lagged behind my typing —and I'm not that fast a typist. In the case of LaTeX this is a well-known problem that's addressed in the manual (see :help tex-slow). I tried all the tips the manual suggested and Vim still lagged, the only thing that fixed it was turning off syntax-highlighting completely. On a whim I tried Emacs, saw it was perfectly snappy (like Vim with non-LaTeX files) and switched.
https://vimhelp.org/syntax.txt.html#tex-slow