Hello, We are using JRockit with JBoss 4.2.3-GA. We use the following arguments to start JBoss. These parameters helped us to increase performance of JBoss, though they might not be perfect and if anyone can suggest something better that would be great. JAVA_OPTS=" -Xms2047M -Xmx2047M -jrockit -Xgc:parallel -Xverbose:memory -Xgcreport -XXaggressive -XXlazyunlocking -XXtlasize:min=4k,preferred=512k -XXcallprofiling -Djava.security.policy=$JAVA_HOME/lib/security/java.policy" As you can see these arguments are specific for JRockit jvm. For the experiment we might switch from JRockit to SUN JVM. These arguments: Xgc:parallel -Xverbose:memory -Xgcreport -XXaggressive -XXlazyunlocking -XXtlasize:min=4k,preferred=512k -XXcallprofiling are specific for JRockit JVM and in SUN they are defined differently. I have found some SUN equivalents, but not 100% sure they are correct. Can anyone please advice on SUN equivalents for these JRockit arguments? View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4185826#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...