Fix Minecraft server lag

TPS, MSPT, ping, FPS – what's what?

Rule of thumb: if everyone suffers at once, it's the server (TPS). If only one player does, it's their connection or their PC. No server tuning fixes ping or FPS.

Step 1: Measure, don't guess

Paper has two quick console commands (in the AvantaHost panel: the Console tab):

tps    # TPS over the last 1, 5 and 15 minutes
mspt   # time spent per tick

If TPS sits at 20 and MSPT is well below 50, the server has headroom – look at ping or FPS instead. The Overview tab is worth a look too: if CPU constantly sits at your package's limit, that's a clear sign.

Step 2: Find the cause with spark

spark shows which part of the server eats the time: a plugin, a mob farm, redstone or chunk loading. Since Minecraft 1.21 spark ships with Paper. On older versions and other software (Fabric, Forge) install it as a plugin or mod from spark.lucko.me.

# Start the profiler, stops automatically after 10 minutes
spark profiler start --timeout 600

# or start and stop manually
spark profiler start
spark profiler stop

# Only record ticks longer than 60 ms (great for short lag spikes)
spark profiler start --only-ticks-over 60

# Overall health: TPS, MSPT, CPU, memory, disk
spark health

spark ends with a link to the report. Expand the tree under the server thread and follow the largest percentages. Typical findings:

• A plugin name at the top → update it, check its settings or replace it.
• entityTick / lots of entities → mob farms, dropped items, too many animals in one spot.
• Chunk generation → players exploring new areas. Fix: pregeneration (step 5).
• Hoppers and redstone → large sorting systems and clock circuits.

Step 3: view-distance and simulation-distance

This is the most effective single lever. Both values live in server.properties (Files tab) and are measured in chunks:

• view-distance: how far players can see the world. Mostly costs bandwidth and memory.
• simulation-distance: the radius in which mobs, crops and redstone are actually processed. Costs CPU – and it grows with the square of the radius.

# Both default to 10
view-distance=8
simulation-distance=6

A radius of 6 instead of 10 means roughly 169 instead of 441 simulated chunks per player – less than half. Players barely notice, and farms keep working as long as someone is nearby. Don't forget to restart.

Step 4: Tune Paper settings

If your server still runs Vanilla, switching to Paper is the biggest improvement of all – fully compatible with normal worlds. Paper also adds config/paper-world-defaults.yml. A few options that barely change gameplay:

collisions:
  max-entity-collisions: 2          # default 8
environment:
  optimize-explosions: true         # default false
chunks:
  max-auto-save-chunks-per-tick: 8  # default 24, smooths auto-save spikes

Use these with care – they change behaviour:

Change only a few values at a time and measure again with spark. Every option is explained in the Paper documentation.

Step 5: Pregenerate the world with Chunky

Generating new chunks is one of the most expensive things a server does. When players fly through unexplored land with elytra, TPS collapses. The fix: pregenerate the world while nobody is playing and set a world border.

Install the Chunky plugin (from Hangar or Modrinth) as described in Install Minecraft plugins. Then in the console:

# World border: 10,000 blocks across, centred on 0,0
worldborder center 0 0
worldborder set 10000

# Chunky takes centre and radius from the world border
chunky world world
chunky worldborder
chunky start

# Progress, pause, resume
chunky progress
chunky pause
chunky continue

Repeat for the Nether and the End with chunky world world_nether or world_the_end (a smaller radius is enough there).

Step 6: Typical in-game lag sources

• Too many animals in pens (hundreds of cows in one spot). Limit breeding.
• Dropped items, e.g. from broken farms. Remove them from the console with kill @e[type=item] – careful, this deletes every currently loaded item drop.
• Redstone clocks that run constantly, even when nobody uses the build.
• Plugins that scan the world (some anti-xray or logging plugins with the wrong settings).
• Outdated plugins after a Minecraft update – spark reliably points them out.

Myth: more RAM makes the server faster

The most common misconception. Minecraft processes the world mainly on one thread – TPS depends on single-core CPU performance, not on memory. You need enough RAM, but no more:

• Paper recommends 6–10 GB for most servers, even with few players. Small vanilla groups get by with less.
• Beyond a certain point, more RAM gives “minimal returns” according to the Paper docs – 32 GB for a normal server is wasted money.
• Too much RAM can even hurt: the garbage collector has more to clean up and pauses get longer.
• You can spot too little RAM when spark health shows a nearly full heap and frequent GC pauses – or a crash with OutOfMemoryError.

Bottom line: almost always measure and tune first. A bigger package mainly helps when spark shows a CPU that's constantly maxed out even though view distance, entities and plugins are reasonable.