For some time I have been having strange lagspikes, and I have found out that those come from the CPU spiking to 100%. My server host claims that MC is single threaded (addtional background info) Spoiler (Move your mouse to the spoiler area to reveal the content) Show Spoiler Hide Spoiler Now my server host claims that MC is single threaded and that there is nothing I can do about it exept reducing plugins (even though this setup has been running fine for months, and only started lagging since CB1k ) They claim I should pay extra to increase my RAM, but acording to the commandbook /debug info command I never actually run out of RAM, so I'm not gonna do that. So, I seem to remember that bukkit is multihreaded, I would like to know from people who really understand bukkit if this is true, and in what measure. Are worlds in seperate threads? are plugins? what more? Or is the majority of all bukkit-stuff still locked in one big thread? (I also remember that was one of the issues with hmod... so I take it the Bukkit team solved that, but I would like to know for sure). I would like to have some solid information on this topic to slap my host in his face because I suspect he simply only gives me 1 core out of 8 so he can host 8 servers on one machine... if that is the case I should be looking for another host, or have a serious conversation with my current one.