The server seems to lag quite often, however there is always considerably less lag after each of the 6 hour restarts.
This period of reduced lag seems to only last for 2-3 hours until the server feels slow again (though this probably varies from player to player). My suggestion for now is to add more frequent restarts, perhaps every 2-3 hours instead of 6). We would lose only 5-10 minutes of playtime, but we would get more out of each session. What do you guys think?