pg_restore taking 4 hours!

Hi!

I am using PostgreSQL with a proprietary ERP software in Brazil. The 
database have around 1.600 tables (each one with +/- 50 columns).
My problem now is the time that takes to restore a dump. My customer 
database have arount 500mb (on the disk, not the dump file) and I am 
making the dump with pg_dump -Fc, my dumped file have 30mb. To make the 
dump, it's taking +/- 1,5 hours BUT to restore (using pg_restore ) it it 
takes 4 - 5 hours!!!

Our machine it's a Dell Server Power Edge 1600sc (Xeon 2,4Ghz, with 1GB 
memory, 7200 RPM disk). I don't think that there is a machine problem 
because it's a server dedicated for the database and the cpu utilization 
during the restore is around 30%.

Looking on the lists arquives I found some messages about this and Tom 
Lane was saying that then you have a lot of convertions the dump can 
delay too much. 90% of the columns on my database are char columns and I 
don't have large objects on the database. The restore is delaying too 
much because the conversion of the char columns ? How can I have a 
better performance on this restore?

I need to find a solution for this because I am convincing customers 
that are using SQL Server, DB2 and Oracle to change to PostgreSQL but 
this customers have databases of 5GB!!! I am thinking that even with a 
better server, the restore will take 2 days!

My data:
Conectiva Linux 10 , Kernel 2.6.8
PostgreSQL 7.4.6.

postgresql.conf modified parameters (the other parameters are the default)
tcpip_socket = true
max_connections = 30
shared_buffers = 30000
sort_mem = 4096 
vacuum_mem = 8192
max_fsm_pages = 20000
max_fsm_relations = 1000

Regards,

Rodrigo Carvalhaes