Hi lowecg2004, Thanks for the tip. Just modified the jpa-no-a4j.ear application adding : anonymous wrote : <core:init debug="false" /> But same results than before (looking at Seam code, debug="false" is the default value). So, for a constant throughput of 60tx/s, I have the following results : cpu used=40% elapsed(ms)=94ms for a 5 minute long load-test. Thanks you once more anyway ! View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4111947#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...