Performance

How to Reduce Minecraft Server Lag (Get TPS Back to 20)

A laggy server isn't about your internet, it's the tick rate. Here is how to push TPS from single digits back to a clean 20 with a handful of config changes and one profiler run.

survival ~ screen -r mc
Ticks / second
05101520
/tps => 12.4 (lagging)
set view-distance: 10 → 6
set simulation-distance: 10 → 5
jar spigot.jar → paper-1.21.jar [swapped]
[spark] entities/chunk capped → 32
/tps => 20.0 (*)▋

The 50ms budget

1
Measure the real TPS
Run /tps in-game or /spark tps. Anything under ~19 means ticks are taking longer than 50ms and players feel rubber-banding.
2
Drop view & simulation distance
In server.properties set view-distance=6 and simulation-distance=5. This is the single biggest win on a crowded or low-RAM box.
3
Switch to Paper
Replace spigot.jar / vanilla with paper-1.21.jar. Paper async-loads chunks and ships per-world tuning in config/paper-world-defaults.yml.
4
Cap entities per chunk
In paper-world-defaults.yml lower entity-per-chunk-save-limit and mob spawn caps; clear hoarded item frames and named animals.
5
Profile what's left
Run /spark profiler --timeout 120, then open the report. It names the exact plugin or chunk eating tick time so you fix the cause, not guess.

What you need

Tick rate / TPS

Spark profiler

Entity limits

Paper / Purpur jar

Quick answers

What is a good TPS?

20 TPS is perfect. Each tick should finish in under 50ms. Sustained values below 19 mean the server is behind and time effectively slows for players.

TPS vs FPS, what's the difference?

FPS is your client's render rate. TPS is the server's simulation rate. Low FPS is a video-card issue; low TPS is a server issue and affects everyone equally.

Does more RAM fix lag?

Rarely past 6-8GB. Most lag is CPU single-thread bound or caused by chunk/entity load, not RAM starvation. Over-allocating RAM can even worsen GC pauses.