If Vim isn’t responsive in a machine with hundreds of MHz something is very wrong with your setup. Vim was fast on machines with dozens of MHz. Either a bad terminal emulator or some plugin making it slow, I’d guess.
So there are two problems I guess, user-based and technical.
User problem: since I use Vim for everything, my expectations as far as responsiveness goes are probably not calibrated correctly. It is almost always very good, so the moments of badness are noticeable. The user (me) is unreasonably picky.
Technical: LaTeX syntax highlighting. It is I’m pretty sure, generally known to be a bit of a pain. Lots of nested environments that can go back dozens of lines and change how commands are interpreted. It is happy in a decent (not huge or anything) sized Fortran code, so I think config is mostly OK. Maybe I should look around and see if there’s a nice LaTeX plugin out there.
Some vim plugins are slow. Fortran highlighting used to be super slow for certain use cases 10 years ago. I think there were some bad regexes. Latex documents are often long (cf other code) and the syntax rules are complex.
There are definitely some pathological situations where vim becomes unresponsive even on a beefy box. Usually there's exceptionally long lines of text involved, esp. with syntax highlighting/:setf active IME.
Furthermore there's the whole intentional delay on ESC exit from modes like an aborted search query... that can make it feel unresponsive but it's just a timeout. Try it, hit '/' in vim, then ESC to abort the search, count a full second of unresponsiveness.
This blog speaks to such ESC delays one encounters in vim:
According to https://vt100.net/heath/z19-om.pdf it can do 110 to 9600 baud. It was connected to some Z8000 based Onyx server. It was generally good but incredibly slow when more than four or five of us were compiling code for the tests at university class. Pascal, Berkeley p system or something with a similar name.
It's not vim, but the OS/graphical system that you are most likely using underneath. While having Firefox/Chromium open for reference to what you are working on.
Specifically worth comparing terminal emulator performance. I noticed that for example (not surprisingly I guess) alacritty has been both the worst and the best depending on the setup.
