Is it true that by using JMS/MDBs (asynchronous processing) vs. SLSBs (synchronous processing) we can definitely improve the performance of our app?  We have an event processor that is only utilizing approx. 14% of a multi-CPU multi-core JBoss 4.2 server.

I know that SLSB and MDB are both in a pool in the app server and this pool size is configurable...