Minecraft server lagging? Find the cause and fix it

Blocks reappear, animals jump, doors open late? Then the server can't keep up. Usually one of the common causes below is behind it, and a profiler tells you which one.

5 min read · Updated 16 October 2026

Server lag or connection lag?

A Minecraft server recalculates the world 20 times a second, that's the TPS (ticks per second). Each tick may take at most 50 milliseconds. If it takes longer, TPS drops and every player notices at the same time: that's server lag. If only one player stutters while the others play smoothly, it's usually their connection or PC, not the server.

If the log says Can't keep up!, it's server lag. Right after a start that's normal because the world is loading.

The most common causes

• Items on the ground: farms without collectors or blown-up bases leave thousands of items lying around. Every single one is calculated every tick.
• Villagers and animals: many mobs in a small space cost pathfinding and collisions. Big trading halls and animal farms are typical culprits.
• Hoppers: every hopper constantly checks whether there's something to pick up. Hundreds of them add up.
• Redstone clocks: circuits that pulse non-stop load the server even when nobody is nearby, as long as the chunk is loaded.
• New chunks: flying fast into unexplored areas makes the server generate terrain. That's expensive, especially with elytra.
• A plugin or mod: some extensions are badly written or misconfigured and eat most of every tick.
• Too little memory: if RAM is almost full, Java has to clean up all the time and pauses the server while doing it. It looks like lag in short bursts.

Finding the culprit

Guessing rarely helps. A profiler shows what the server spends its time on. A popular one is spark: on Paper and Purpur, type /spark profiler start, play for a few minutes and finish with /spark profiler stop. The link shows which mod, plugin or part of the world costs the most time. On Fabric, Forge and NeoForge you install spark as a mod.

What helps

• Limit items and mobs: clear items, add collectors to farms, spread villagers over several halls, shrink animal farms.
• Lower the simulation distance: setting simulation-distance in server.properties to 6 to 8 often helps the most without anyone noticing.
• Pre-generate the world: with Chunky you generate the world around spawn in advance, so the server doesn't have to do it while people play.
• Optimised software: Paper instead of vanilla, Lithium and FerriteCore on Fabric. They calculate the same thing much faster.
• Update or remove the slow extension: if a mod or plugin is at the top of the profiler, an update often already helps.
• More RAM: only if memory really is tight. More RAM doesn't make an overloaded processor faster.

How it works at Navoryx

With us, Navoryx Insight is built into every Minecraft server, no plugin needed. It measures TPS all the time and shows in the Panel under Leistung (performance) what the server spends its time on: which mod or plugin, which entities, hoppers, redstone or chunks, including the spot in the world with a teleport command.

1. Open your server in the Panel. The Leistung tile shows TPS and milliseconds per tick.
2. If the server lags, the analysis appears above the console: the main cause, the shares and the places with the most entities.
3. Under Lösen mit einem Klick (fix in one click) you get matching actions, for example removing items, easing villagers or hoppers, faster redstone or installing Lithium. It tells you beforehand what happens and whether the server restarts.
4. Changed settings are backed up first. Under Gemacht (done) you undo them with one click.

Insight runs on Paper, Purpur, Spigot, Vanilla, Fabric, Quilt, Forge, NeoForge, Mohist, Arclight, Folia and many more, from 1.7.10 to the current version, and on proxies like Velocity and BungeeCord. We tested it on 45 server types.

Frequently asked questions

Read more

• How to make a Minecraft server: play with friends in minutes
• How much RAM does a Minecraft server need?
• Paper, Fabric, Forge or NeoForge: which server software?