I have around 1000 users on my server. Mostly car dealers. Im having some problems that are being worked on but I am curious what your memory use is with your smartermail server. For mine, mailservice.exe reports about 1.1 to 1.3 GB of memory use at around 9am EST. Also 88 threads, 14million page faults, 2555 handles. That's about 24 hours after the last restart of the service.