Recommended JBoss and Tomcat memory settings?

[Alexander Yap]

Hi all,
Can someone recommend appropriate JVM memory settings ( -Xms and -Xmx ) to start Tomcat and JBoss for best performance?
Is there some guidelines for choosing these values based on available RAM?
I have a single machine running:
- Sun JDK 1.4.2
- MySQL Max 4.0.11
- JBoss 3.2.2 (just serving EJBs)
- Tomcat 4.1.x (running 5 Web apps, 3 of which connect to EJBs on JBoss)
- 1 Swing application (GUI controller for a chat server)
Note: The Tomcat and JBoss are separate installations, not the JBoss bundled with Tomcat.
Machine specs:
CPU: Pentium 4 2.2 GHz
RAM: 1 GB
OS: Mandrake Linux 9.1 + KDE 3.1

Thanks.
Alexander Yap
Melbourne, Australia