Entity Tick Optimizer (ETO)

Entity Tick Optimizer is a powerful, highly configurable server-side performance mod for Fabric that intelligently throttles entity AI and ticking based on distance to players.

Overview

Instead of ticking every mob at full intensity all the time, Entity Tick Optimizer uses a 4-tier activation system to dramatically reduce server CPU usage in large worlds, mob farms, or high-entity-count servers, while keeping gameplay responsive near players.

Core Features

• 4-Tier Activation System:

  • FULL — Normal vanilla behavior (close range)
  • REDUCED — AI runs at reduced frequency
  • INACTIVE — Very minimal AI + throttled base ticking
  • MINIMAL — Physics-only (extremely distant entities)

• Highly Configurable:

  • Separate settings for each mob category (monster, creature, ambient, water_creature, etc.)
  • Full per-entity overrides (e.g. make zombies more active than skeletons)
  • Adjustable ranges and AI intervals

• Smart Lithium Compatibility:

  • Automatically disables main throttling when Lithium is detected (recommended)
  • Can be forced on if desired

• Performance Statistics & Commands:

  • /entitytickoptimizer stats — View detailed throttling statistics
  • /entitytickoptimizer stats reset — Reset counters
  • /entitytickoptimizer reload — Reload config
  • /entitytickoptimizer debug <entityType> — Check activation level of nearby mobs

How It Works

The mod intercepts the main entity ticking loop and applies distance-based rules before entities even begin their normal tick cycle. This is significantly more effective than simple AI skipping for distant mobs.

Additional optimizations are applied via mixins to LivingEntity and Mob for further savings on block checks, base ticking, etc.

Configuration

Edit config/entity-tick-optimizer.json for full control. The config is well-documented and supports:

• Custom ranges for each tier
• Per-entity overrides using entity IDs (e.g. minecraft:zombie)
• Global enable/disable and debug options

Compatibility

• Minecraft 1.21.11
• Fabric Loader
• Works alongside Lithium (recommended to keep default compatibility mode)
• High mixin priority to compete with other optimizers

Note: This is a server-side mod. Clients do not need it.