RAM is not the same as Java heap. Looking at RAM usage typically does not mean much. Unless you analyze the Java heap usage, it is difficult to say how much memory the app is really using, or how much it really needs. JBoss AS by itself does not need much (64M is probably more than enough), and unless you have a very unusual application I doubt that your application would need 14G of heap. And yes the settings I gave are starting points. You need to analyze the heap usage and adjust those accordingly. I thought occurred to me that the JVM, if given the opportunity (such as offered by your initial heap settings) might grab a significant chunk of memory if it is available. If I have some time, I might wrestle one of our Windows boxes from the performance team and try it out, or maybe one of them knows off-hand. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4077856#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...