I asked about this a few years ago on SO and there is some good info: https://stackoverflow.com/q/61338780/265521

E.g. Chrome has this comment:

  // Chromium uses a minimum timer interval of 4ms. We'd like to go
  // lower; however, there are poorly coded websites out there which do
  // create CPU-spinning loops.  Using 4ms prevents the CPU from
  // spinning too busily and provides a balance between CPU spinning and
  // the smallest possible interval timer.

Seems like it has been removed though based on jayflux's comment.