Missing performance tip? Fonts/XFree

[Steve Hutton]

The performance tips page -
http://dforce.sh.cvut.cz/~seli/download/tips.html

doesn't mention something that I've heard
people talk about as affecting KDE performance -
the version of XFree86 (and fontconfig?).  I'm
unclear on the details, but apparently older
versions of XFree do not load fonts on demand?

Are there performace implications with adding
more fonts to a system?  Under all versions of
XFree, or just some?

Steve