How to Diagnose Entity Lag on a Minecraft Server

Direct answer

Run a spark profile while the affected farms/areas are loaded. If entity ticking, AI/pathfinding, collisions, or a plugin's entity listeners dominate the profile, find which entity type and location creates the load before changing global settings.

Why entities become expensive

• AI and pathfinding for villagers and mobs.
• Large numbers of dropped items, XP orbs, minecarts, boats, or projectiles.
• Collision checks in dense farms or cramming setups.
• Plugins/mods that run logic for every entity tick, move, damage, spawn, or target event.
• Many active chunks caused by high simulation distance or players spread across the map.

Find the source instead of only the count

Ten complex modded entities can cost more than hundreds of simple entities. A raw entity count is a clue, not a diagnosis. Use spark's call tree and reproduce the problem near the suspected area.

Paper settings to approach carefully

Paper exposes settings that can reduce specific costs, including entity collision limits, armor-stand ticking, pathfinding updates, spawning behavior, and other entity options. These can change gameplay. Change them only after confirming the workload and reading the current Paper documentation for your version.

Practical fixes

Prefer targeted changes: redesign a pathological farm, remove abandoned entities, fix a plugin/mod doing excessive work, reduce active simulation area, or limit a specific server feature. Re-profile afterwards.

References

These sources were checked while preparing this article. Performance behavior and configuration can change between Minecraft/server-software versions, so verify version-specific settings before applying them.

• PaperMC: World configuration
• PaperMC: Profiling
• spark: performance profiler for Minecraft
• PaperMC: server.properties reference

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