Emacs scrolling (redisplay) is very slow in Windows XP after the font backend enabled.
 
e.g., if I open a file £¨quite large£©, when I press PageDn/PageUp to scroll it, there is an uncomfortable delay in the redisplay. If I hold down the PageDn/PageUp for a while, the delay is even worse and Emacs will lose response for a while.
 
In Emacs-22.2 and the 23 version where the font backend disabled, the scrolling is very fluent when I hold down the PageDn/PageUp key.