Emacs 24: Spell-Checking on Windows is 25 Times Faster!

Just discovered something incredible. For emacs on Windows, calling flyspell-buffer usually takes 5 seconds for a small file (e.g. 8k sized).

But in emacs 24, it is now less than a second!

Was there a change in emacs 24 that effected this or am i smoking something?

Here's a exact timing, on a 80k HTML file:

  • emacs 23.2.1 on Windows (with Cygwin aspell): 80 seconds
  • emacs 24.0.93 on Windows (with Cygwin aspell): 3 seconds

the release notes (aka emacs NEWS) didn't mention anything about spell, but has the following:

** The default value of redisplay-dont-pause is now t
This makes Emacs feel more responsive to editing commands that arrive
at high rate, e.g. if you lean on some key, because stopping redisplay
in the middle (when this variable is nil) forces more expensive
updates later on, and Emacs appears to be unable to keep up.

however, setting “redisplay-dont-pause” to t, didn't help in emacs 23.