Is this Linux? Are you using libaio? What disk you have in your config? If you are using linux/libaio, when you add more clients you should scale even higher. I mean. Our target for BETA is to maximize your disk... say.. if your disk can do up to 20K messages a second on the disk, you would be able to add 20 more producers and you would still have 800/1K messages per second on each producer. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4159781#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...