Beta4 is slower. On my Windows desktop it takes twice as long to start Beta4 as 4.2.2. Which is pretty good, Beta3 took 5 times as long.
I have also noticed a long wait (several seconds) to access the first page of the jmx console, and again when accessing the first mbean in the jmx console. In 4.2.2, I usually get the response back in under a second. But after that the pages are served quickly (less than a second)
I haven't really tried out any other performance measures. But usually most of the performance changes go in after the release candidate and before GA. This has been the pattern for the last several releases in which I have tracked this.
Thanks PeterJ what you said does make sense. I will hold off a while longer on trying JBoss 5b4 until the production release.