Minecraft Bedrock: Why Is My Add-on Causing Extreme Lag/FPS Drops? (2026 Performance Fix)

Quick Answer

Your add-on causes extreme lag, FPS drops, or world freezes because of runaway script loops (executing every tick), entity spam from uncontrolled spawning, high-resolution textures without mipmaps, particle effect overload, or overly complex Molang expressions. The fix: add tick throttling to scripts, limit entity counts, use 16x/32x textures with mipmaps, cap particle counts, and simplify Molang math.

Top 5 Performance Killers (July 2026)

• Runaway Script Loops: Code in system.runTick() or world.beforeEvents.worldTick without throttling runs 20x/second — destroys performance.
• Entity Spam: Spawning entities in loops without limits (e.g., particle entities, projectile spam) crashes servers/clients.
• High-Res Textures Without Mipmaps: 512px+ textures on mobile/Switch eat VRAM; missing mipmaps cause texture thrashing.
• Particle Effect Overload: minecraft:particle_effect components with high max_particles or frequent triggers.
• Complex Molang in Animations/Render Controllers: Math-heavy expressions (trig, noise, many conditionals) evaluated per-vertex/frame.

Step-by-Step Fixes

1. Throttle Script Execution (Critical)

Bad (runs every tick):

import { system, world } from "@minecraft/server";

system.runTick(() => {
  // This runs 20 times/second — LAG!
  const players = world.getPlayers();
  players.forEach(p => { /* heavy logic */ });
});

Good (throttled to every 20 ticks = 1 second):

import { system, world } from "@minecraft/server";

let tickCounter = 0;
system.runTick(() => {
  tickCounter++;
  if (tickCounter % 20 !== 0) return; // Run once per second
  
  const players = world.getPlayers();
  players.forEach(p => { /* heavy logic */ });
});

Better: Use system.runInterval (v26.0+):

import { system, world } from "@minecraft/server";

system.runInterval(() => {
  const players = world.getPlayers();
  players.forEach(p => { /* heavy logic */ });
}, 20); // 20 ticks = 1 second

2. Limit Entity Spawns

Always cap entity counts and clean up:

import { world, system } from "@minecraft/server";

const MAX_ENTITIES = 50;
let activeEntities = [];

function spawnParticleEffect(location) {
  if (activeEntities.length >= MAX_ENTITIES) {
    // Remove oldest
    const old = activeEntities.shift();
    if (old?.isValid) old.remove();
  }
  
  const entity = world.spawnEntity("minecraft:glow_particle", location);
  activeEntities.push(entity);
  
  // Auto-cleanup after 5 seconds
  system.runTimeout(() => {
    if (entity.isValid) entity.remove();
    activeEntities = activeEntities.filter(e => e !== entity);
  }, 100); // 100 ticks = 5 seconds
}

3. Optimize Textures

Add mipmaps in manifest.json texture entry:

"texture_data": {
  "my_texture": {
    "textures": "textures/blocks/my_block",
    "filter": "linear_mipmap_linear"
  }
}

4. Cap Particle Effects

// In entity JSON - limit particle count
"minecraft:particle_effect": {
  "effect": "my_custom_particle",
  "max_particles": 20,  // Never exceed 50 per entity
  "lifetime": 1.0
}

5. Simplify Molang Expressions

Heavy (per-vertex):

"scale": "Math.sin(query.life_time * 20) * 0.5 + 1.0"

Light (pre-compute in script, pass as variable):

// Script (runs once per second)
system.runInterval(() => {
  const scale = Math.sin(Date.now() / 1000 * 20) * 0.5 + 1.0;
  entity.setProperty("custom:scale", scale);
}, 20);

// Render controller (just reads variable)
"scale": "query.custom:scale"

Profiling: How to Find the Bottleneck

• Windows 10/11: Press F3 + L for profiler overlay; check “Script” and “Render” times.
• All Platforms: Check content_log.txt for [Script] Warning: Long running script detected.
• Realms: Use /script watchdog command to see script execution times.

Still Lagging?

Disable add-ons one by one to isolate the culprit. Also see our guides: v26.0+ Breaking Changes and Import Issues.

Updated for Minecraft Bedrock 1.21.20+ (v26.0/v26.2), July 2026.