Quoting Erik Sandberg <address@hidden>:
...
BTW, some watching of the process leads me to think that one of the
biggest performance sinks is conversion to PDF.
Sounds very strange. However, if ps->pdf conversion does take forever,
then
you can always use the --ps switch to lilypond (which skips the pdf
generation phase).
Unfortunately, that's not true on Windows, where it seems that GSView
is unable to handle Postscript files from LilyPond, no matter what
ghostscript version you use. See the mailing list archives for more
information.