I've never run OS X Server before. I know 10.6 Server is a separate install, while in newer versions of OS X it's an add on to the base installation. Yes I know it will run all the way up to El Capitan. I'm using this machine as a server (plex, file sharing, VPN, torrentbox). I was going to keep it old school and run 10.6 but I was wondering what you all thought the sweet spot for performance would be for this machine. Perhaps Mountain Lion, or Mavericks? Running 10.6 it's just a hair too slow for plex server to do high bitrate 1080p transcodes. I was hoping (perhaps erroneously) that something like Mavericks might have better performance. I've included a poll as an experiment but please post your thoughts. Thanks.