Server NW6.5 sp 4a, Zen 6.5 sp 2

This server is having cache allocator problems. Something is chewing up
memory. I've been running seg.nlm as suggested elsewhere, but after five
days it didn't show anything climbing significantly. I have a concern,

The entire system contains maybe 400 PC's. Yet when the zen inventory
database loads, it sucks up over 200 meg of memory!

That seems awfully high to me. Is this normal?