KDE4 slow on old machine

One of my students just installed MDV2009.1
on an older desktop machine, and was telling
me that KDE appears subjectively significantly
slower than Gnome or XP on that machine (e.g.,
when starting apps or moving windows around).
I have not noticed such behavior, but I am using
2009.1 on only much faster, modern machines.  Has
anyone else noticed this?  Any settings changes
one can make to KDE4 to affect this?

Also wondered why this might be so?  I thought
a goal for KDE4 was to be faster/less RAM and able
to run on handhelds, etc.  Guess it uses vector
graphics in places instead of bitmaps, so that will
probably take some CPU cycles.  Perhaps this is a
graphics issue?  Didn't get all the details, but
this is a 5+ yr old machine with an Nvidia graphics
card in it.  Can find out more details if of interest.
Norm