Message passing on my new machine when sending messages between actors which have the same mailbox is about 150,000,000 per second, which is just a bit faster than when passing messages between actors which have different mailboxes.
We used to report a much higher number, but then we fixed an exception handling bug. And while before we would just pass naked requests when the mailboxes were the same, now all messages must be wrapped--which used to only apply when passing messages across different mailboxes.
We may still be able to regain some of the lost performance in JActor 4. See github.com/laforge49/J...
Meanwhile, we are getting 1 million fully durable transactions per second with JFile's in-memory database. So things aren't all bad. :-)