I have a FC5 server with 512 MB of memory. I'd like to migrate from sendmail/dovecot to Zimbra. The machine is likely to have only 4-6 users, as it's for family email only. Most will be using IMAP clients such as Apple Mail and Thunderbird. There will be some smartphone clients as well.
512 MB is below the recommendation -- but will it be useable? I installed the open source version on a similar machine and fooled with the web ui for a few minutes, and it seemed ok. Once actually processing mail on the internet, though, and with 4-6 simultaneous actual clients, will it swap to death?