What operating system? Windows tends to swap things out to disk even when it doesn't need to. What are your JVM heap settings? Also, you might get better performance if you limit the app server to running on 2, 3 or 4 of the Opterons(sockets). We have found that after 4 sockets that either you get no additional performance benefit or performance drops. And that some deployed apps run better on 2, others on 3, and others on 4 sockets. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4077444#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...