Will your users be using exclusively the Web Client or IMAP/POP; or a mixture?
In our LAN environment, we run Zimbra on a Dell PowerEdge 2950 - Dual Quad-core Xeon 2.2GHz (each), 8GB RAM, 15,000rpm SAS drives and Gig ethernet. With 1000 accounts we have around 120 concurrent users (web client) at peak times and there is no degradation in performance. Load average stays below 1 and there's usually between 2-4GB RAM free and no swap usage.
Hope that helps. |