Hi Manik yes it might be serialization. But still with the async tag, this serialization is supposed to happen asynchronously after the commit right? So by definition it shouldn't increase latency. I have reduced the latency a lot (more than half) by: -using invalidation instead of replication -setting a Heap size that is a bit more than what is really used, instead of the big heap i used before But it is still a bit slow, and CPU usage (another of our requirements) is at 50% instead of 10%. Isn't a 50% CPU load too much for this use case? (A and B are quad-core 2.33GHz 4G RAM, linked by a 100Mega switch (yes that is slow but this too is a requirement)) At any rate from what i saw in VisualVM i suspect that the threads that i mentioned are what makes CPU usage so high. Anyway any clue? What can i do to investigate further? View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4270138#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...