Dear Peter, What you said earlier in the thread suggests that it is not so much having a massive heap that is an issue, but having too many objects end up in the tenured generation that are really too young. By increasing the size of the young generations, you are effectively raising the age at which objects pour over into the tenured generation. Also, would using a parallel garbage collector not alleviate the pausing? Kees Jan View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4172198#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...