Improve ODBC Throughput ?

Hi list !

I mostly use my PostgreSQL as a backend DB with Access2000 
frontends.
The tables are linked via psqlODBC.
The problem I have is that even though queries / views run 
very fast, the data take a long time to arrive to the client.
In the best situations, data is sent/received at ~500kB per 
second (for instance, tables with only one column, which is 
a very large text field >10.000 bytes per field).
In bad situations, I am at ~50kB per second.
If the queries / views return large resultsets, it can 
seconds for the table to open., even though the query ran in 
milliseconds on the server (explain analyze proves this).

What can I do to improve this throughput ? Either on the 
server side, or on the ODBC client side ?

As a side note : network congestion, server acitvity is not 
a good explanation. This server also is a file server, and I 
transfer files at 10MB per second all the time.

Thanks for your advices !
--
Arnaud