We have a Jboss server running on a 64-bit windows server with jdk6(64 bit) . Here is a snapshot the memory usage as viewed from jconsole. Heap Memory Usage : Used : 103 MB, Committed : 295 MB, Max : 571 MB Non-Heap Memory Usage: Used : 47MB, Committed : 47 MB, Max : 115 MB Memory Usage as viewed from task manager : 314 MB Running GC did not have much of an effect on the numbers. The total used memory is 150 MB but the total committed memory is 342 MB. How does JVM decide on the amount of committed memory ? Here are the jvm options: -verbosegc -Xloggc:gc.log -Xms150m -Xmx600m -Xmn125m -XX:+UseParallelGC -XX:ParallelGCThreads=20 -XX:MaxHeapFreeRatio=40 -XX:+PrintGCDetails -XX:+PrintGCTimeStamps -Dsun.rmi.dgc.client.gcInterval=60000 -Dsun.rmi.dgc.server.gcInterval=60000 We are planning to deploy more such jboss server configurations on the same machine. So we are afraid we may run out of memory. Can somebody please help us out ? View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4220988#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...