I know you guys are hard at work trying to find problems relating back to major and servere lag spikes in game and server crashes While i was admin on another server we had very similar problems and we could not figure out what was happening after upgrading servers multiple times the lag still was there. wtf why was it still there and answer for us was simple in the end we started with automatic scheduled restarts of the server every 1hr 30mins http://forums.bukkit.org/threads/admn-simplerestart-v1-1-0-simple-server-automatic-rebooting-and-commands-1000.24652/ also limiting the map size was the most effective way to limit lag on the server most effective on servers that deal with over 100 players at a time and for servers using multiverse with 3+ worlds of unlimited size http://forums.bukkit.org/threads/mech-worldborder-v1-5-0-feature-rich-world-size-limiting-plugin-1-0-1-r1.11309/ These seemed to eliminate most of the lagg Just some suggestions Peace.