anonymous wrote : I'd recommend to try it with pessimistic locking. Not sure how much of the performance impact it will have but I think it does without further tuning. After changing to pessimistic locking, our test results have dramatically improved. It turns out to be a known issue in 1.2.4 SP1. In case anyone stumbles upon this issue, below is a very useful link referring to the phenomenon. http://wiki.jboss.org/wiki/Wiki.jsp?page=JBossCacheOptimisticLockingPerfo... Also referred to from: http://wiki.jboss.org/wiki/Wiki.jsp?page=OptimisticNodeLocking It would be nice to be able to reach (one of) the above pages from a page titled "Performance we should expect from PojoCache" (http://wiki.jboss.org/wiki/Wiki.jsp?page=JBossCacheOptimisticLockingPerfo...), but that's my opinion. Maybe the results would have been expected - 170 (!) times faster. Thanks for all the help, Lior Neuman R&D Team MailVision LTD View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4018904#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...