I have one client who has been on Zimbra 7.x for a long time now, and they are currently at 7.2.4. We are starting to see a slow down on the server with 75+ mailboxes on an Ubuntu 10.0.4 LTS server with 6GB ram and 2 processors. It's possible that this slow down could be the hypervisor that the VM guest is running on.

I have just installed Zimbra 8.0.4 for a couple of other clients and Zimbra seems significantly faster. I'm just wondering if it because these new 8.0.4 servers don't have any load on them, or if it is because 8.0.x is just that much faster, or if I'm imagining the performance difference.

Has anyone done any benchmark testing?