"john_woo(a)canada.com" wrote : I did try the affinity setting (to 4 cpus for the app), but only 1-2 cpu busy. I guessed b/c all threads running in the same process from the main servlet. There is a fair chance that your application is not as thread-able as you think it is. Do you do any manual synchronisation, or do you make heavy use of libraries that do internal synchronisation? Use JConsole to check that you are not exhausting the Tomcat connector thread pools (or other pools) Also, check that you are running with the server VM http://www.java-monitor.com/forum/showthread.php?t=18. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4171686#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...