How can I improve RT response time?

I am running RT 3.0.7 on Solaris and find response time very poor.
At the moment we have only 320 tickets in the database and a large ticket
has about a dozen transactions with about 20 line comments.

Typically it takes about 20 to 30 seconds to bring up the details of a
ticket.
If I run a similar sql query on the postgres database response is instant.

Other web applications running on the same machine respond instantly.

What is a reasonable response time on other installations?

Where can I begin to look for bottlenecks?

Any suggestions for improvements welcome.

Thanks.

Mike

Versions:
SunOS kyle 5.8 Generic_108528-03 sun4u sparc SUNW,Ultra-5_10
RT rt-3-0-7_01
Postgress postgresql-7.4
Apache apache_1.3.29
Modperl mod_perl-1.27
Perl perl-5.8.0
latest perl modules installed