Does this question relate to JBoss Portal, or are you asking about JBoss Application Server? Why would you expect a 40% performance improvement? My team has done a lot of testing with AS 4.0.5 on various platforms with various databases and the performance differences between JBoss AS running on Windows and on Linux have been minuscule. View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4269213#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...