On minecraft, I've been getting horrible lag on one of my favorite servers.

I checked the ping (by hovering over the bars in the multiplayer menu), and it's great: 35. However, when I join the server, I can't use any items, chat, or see other players move. I own another server hosted in the same place, which have no problems connecting. My friends can connect to the server, but I can't log on to it.

I attempted to log in to other servers and they work great, no problems. I run at 60mbps down and around 20mbps up.

  • 2
    I'm by no means good at the techincal aspects of either minecraft or networking, but it could be caused by a server that is overloaded with various mods and active chunks.
    – user1337
    Jul 6, 2015 at 20:15
  • What version of Minecraft are you running? I have a client-side mod for network debugging that I could give you (assuming you can install mods). Lag is not a very easy thing to pinpoint to a single problem and even if you have a great internet connection (which you do, you have more than enough speed to play MC online), one of the routers between you and the server may have an issue, the server host itself may have an issue with its hardware... There are too many variables to pinpoint the exact issue but my mod can at least tell you whether there is a disconnect or network flood
    – Shadowtrot
    Jul 7, 2015 at 4:09

2 Answers 2


If no-one else but you is experiencing this problem, it might be that your client has not enough memory assigned, and is doing forced garbage collecting every few seconds to make enough room to keep running the game. (N.B. "Garbage collecting" is the process in which unused memory is freed up. Normally it is done when nothing special is going on. Forced garbage collecting occurs when the java application runs out of memory and has to free up memory to keep running).

In the client, go to the start-up settings of the particular version you are running, and add the following JVM arguments:

-Xmx2560M -Xms2560M

Xmx2560M tells the Java virtual machine to allocate a maximum of 2560MB of memory to run the application, which is about 2.5GB. Xms2560M tells the JVM to allocate exactly 2560MB when the application starts. You can set the Xms option lower, but never higher than the Xmx option. It does not help to set the Xmx option higher than the amount of memory that is available after the OS and other processes take their share. If you would allocate more memory, it would need to be swapped from the hard drive, which is a very slow process.


Does the server have any plugins installed? I had an issue once where a plugin corrupted some data relating to someone on my server, and whenever they joined, the server slowed down immensely. I fixed the issue by wiping their player data on all of my plugins. Contact the server owner and ask them to do the same, because that might be the problem.

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