speed up restore from dump

Hello all,

I've been tring to speed up the restore operation of my database without
success.

I have a 200MB dump file obtained with 'pg_dumpall --clean --oids'.
After restore is produces a database with one single table (1.000.000)
rows. I have also some indexes on that table. that's it.

It always takes me about 20 minutes to reload the data, whatever
settings I change.

I have so far touched these settings:
- fsync = off
- shared_buffers = 24MB
- temp_buffers = 24Mb
- maintenance_work_mem = 128MB
- full_page_writes = off
- wal_writer_delay = 10000
- checkpoint_segments = 200
- checkpoint_timeout = 1800
- autovacuum = off

I started with a default instalation. first I changed fsync to off, then
I started touching other cfg params. but I always get around 20 minutes
(21, 19, 18)....

Can I expect these 20 minutes to be significantly reduced ?

What other cfg paramenters shoud I touch ?

Can anyone shed some light on this ?

any faster approach to upgrade from 8.1 to 8.3 ?

thank you

Joao