Maybe it is classloading that is the culprit? Fast-jaxb has no binding time, but the first time you parse requires loading classes. Each JAXB annotated class = 1 Parser class in the model I created. Since JAXB already has had its classes loaded at bind time, this overhead isn't accounted for in the test. View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4257946#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...