How to make bugzilla faster in performance??

I have configured bugzilla on Linux.
Using the sendmailnow option from bugzilla, the processing of the bug is getting delayed. Processing is delayed as the email settings is all checked in the bugzilla administration.
Once all these checks are removed so that mail is not sent, then bug processing is faster.

More details...
Hello,
I'm using Bugzilla with Apache Webserver, MySQL
Database and Perl modules on a Linux m/c. For some
reason unknown, when I create a new bug or make
changes to an existing one, it takes a long time to
process the bug and return with the resulting web
page. My question:
1. How can we configure Bugzilla to be any faster?

I tried setting the sendMailNow option to NO. Even
then, it is very slow. Any other tweaks I need to take
care of?
Any help is appreciated.
Thanks.
Raghava