Slow down on Import

Hi folks,

first some techn. data: SNI-Primergy w/ PII-333, 128Meg and
SCSI-devices, Linux 2.0.36
The following strange behaviour comes up since upgrading to
version 6.5.3 + FreeFile-Patch (hi Tom):
When re-importing a dumped database the job is normally done
in roundabout 8 seconds. When you drop the database and
repeat the step a few times, the speed slows down to at least
1.5 minutes.

Example:

# for i in 1 2 3 4 5
# do
#   destroydb xyz
#   createdb xyz
#   time psql xyz < ./import.db    (small table / 10.000 rows)
#   (output from time: 8.2 seconds up to 1.5 minutes)
# done

There is no additional load on that machine. The main application
(MS-Access w/ ODBC xx.0006) seems sleeping during database-
search - so we tried to figure out the problem and made at least
the above test directly on that machine. Last hint: A complete
copy from "/opt/pgsql" transferred to a another machine shows
the same problem.

What´s wrong? Any ideas?

Regards-Rolf