Minecraft "Can't keep up!" and rubber banding: how to fix

⚡ What the warning means

If your server console shows Can't keep up! Is the server overloaded? Running 2500ms or 50 ticks behind, the server is telling you it has fallen behind. Minecraft tries to run 20 ticks per second, one tick every 50 ms. When ticks take longer than that, the delay builds up, and once it passes roughly 2 seconds (40 ticks) the server logs the warning, at most once every 15 seconds.

A single warning at startup, or while someone explores new terrain, is nothing to worry about. If it keeps coming back, the server is overloaded, and players feel it as rubber banding: you walk forward and get pulled back, blocks you broke reappear, mobs move in jumps. The message never names the cause, so you have to find it.

🔎 Measure first

Don't change settings blindly. These are the tools:

• Vanilla (1.20.3 or newer): /tick query shows the average time per tick. Under 50 ms the server is keeping up; over 50 ms it is falling behind. You need operator permissions.
• Paper (1.21 or newer): ships with the spark profiler. /spark tps reports TPS and CPU usage.
• Forge, NeoForge and Fabric: spark is also available as a mod; drop it into the server's mods folder like any other.

To see what is eating the time, run /spark profiler start --timeout 120 while the server is struggling. Two minutes later you get a link to a report showing which part of the game, which mod or which plugin each tick is spent on.

🗺️ Cause 1: new world is being generated

Generating terrain is one of the heaviest jobs a server does. If the warning shows up when someone explores or flies with an elytra, this is it. The fix is to generate the map ahead of time; we cover it step by step in how to pre-generate your world with Chunky.

📏 Cause 2: distances set too high

Two settings in server.properties multiply the work for every player online:

• view-distance: how many chunks of world the server sends around each player. Default 10; accepts 3 to 32.
• simulation-distance: how far from each player entities keep being updated. Default 10; same range.

Lower simulation-distance to 6 or 8 first and, if that isn't enough, view-distance to 8. Save and restart the server. Values of 16 or more with several players online are often what's behind this warning.

🐄 Cause 3: too many entities

Farms with hundreds of animals, dropped items nobody picks up, villagers packed together, long hopper chains. In the spark report they show up as time spent on entities. Keep fewer animals per pen and switch off farms you aren't using.

🧩 Cause 4: a mod or a plugin

If the report points at one mod or plugin, update it, and if nothing changes, try without it. Also:

• If you play without mods, with or without plugins, Paper and Purpur are server builds designed to perform better than Vanilla.
• On Fabric and NeoForge, the Lithium mod optimises game logic without changing how the game plays. It only needs to be on the server; players don't have to install it.

💾 Cause 5: not enough memory

When RAM is always at the limit, Java spends more time freeing memory and ticks get longer. Check real usage in the panel (how to read the CPU and RAM metrics) and compare it with how much RAM a Minecraft server needs for your mods and player count. On ZentexNode you can move up a plan without losing data if you come up short.

Keep in mind that almost all game logic runs on a single thread. When the problem is a slow tick, removing load fixes it; adding cores does not.

📋 Summary

When it happens	Likely cause	What to do
While exploring or flying	World generation	Pre-generate with Chunky
Whenever several players are on	High distances	Lower simulation-distance and view-distance
Near a base or a farm	Entities	Fewer animals, items and hoppers
After adding a mod or plugin	That mod or plugin	Profile with spark; update or remove
With RAM at the limit	Not enough memory	Check the metrics and your plan