Thanks Peter For your excellent support. During the load test run, I saw that the CPU utilization is around 60-70% I'm setting the PermGen Size to 512m with the params -XX:PermSize=64m -XX:MaxPermSize=512m If I donot set this, I'm quickly getting Out of Memory Permgen Space Error. If I can't increase the heapsize beyond 1700MB(including permgen), Does that mean 2GB/4GB/8GB RAM will not make much difference? If garbage collector is not the culprit for the difference in response times at different intervals, I wonder what else could be the reason...? Will clustering of JBoss help me in meeting the SLA? If yes, can I try the software clustering(with out adding any other hardware), or I have to go with Hardware Clustering only? View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4258791#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...