Performance Mystery

I just did a test using R2004. My lsp driven routine draws many (some
100,000) entities -- mostly single-character text. To make performance
better I modified the routine to split things up, draw no more than 10,000
at a time, Wblock that group to FileName1 (which deletes them from the
database and the display) -- then proceeds with the next group, FileName2,
etc. This way, there are never more than 10,000 entities in the drawing.
In the table below, I list the time in minutes, it takes for each group to
be drawn and Wblocked.
Group) Minutes
1) 2.1
2) 6.3
3) 10.3
4) 24.5
5) 18.5
6) 23.1
7) 42.6
8) 31.1
9) 57.1
10)36.5
Does anybody have any idea for the worsening performance after the first
group?
p.s. Under Win2k Pro I am running this with 1.5 Gb RAM and some 60 Gb
available disk space.
Len Miller