Slow connection to the database

I have a problem with slow connects to a database server.

In a little Java application I am starting 100 threads, each one making
a database connection. The program is running on my laptop.

When connecting to one server (AMD Opteron 2GHz with Solaris &
pgsql version 8.0.3) the 100 connections takes 455 seconds!

Comparing to an old PC (AMD K6-II 500MHz with FreeBSD and pgsql version
8.0.3) the 100 connections takes 6 seconds

When running the client program on the Opteron the 100 connections takes
only 1 second, but in general the network speed to/from the server is ok
and they are on the same LAN.
When they are connected insert and select speed are ok.

Is anyone of you having an idea where to seek the problem ?

Regards, Poul