An enlarged CPD (sounds like a medical problem...) typically
indicates a corrupt CPD file. As a point of reference, my WebHelp
Knowledge Base (in RH7) has over 2000 topics in it, and just shy of
a gig of stuff supported by it. My CPD file is 3MB and working just
fine. If you start seeing slow project access, or even get error
messages about the CPD, it's time to rebuild it - which happens
occasionally. But if it ain't broke, I would say don't fix it.
I learned the hard way that I had to rebuild a corrupt CPD
BEFORE I moved to RH6, which just had all sorts of problems trying
to rebuild it. So luckily you have made it successfully to RH7,
which is much more cooperative.