CurseForge · Minecraft mod
Harium
A general-purpose optimization mod that rewrites inefficient vanilla code for AI, redstone, entities, hoppers, and physics without changing game behavior
Quick answer
Which Harium release should I use?
Harium-mc1.20.1-2.0-cumulative-hotfix-v2.jar targets 1.20.1 with Forge. The project page does not say whether this file belongs on the client, dedicated server, or both. No extra mods listed for this file.
Where it goes
Is Harium required on the client, server, or both?
The project page does not say whether this file belongs on the client, dedicated server, or both.
The source does not explicitly classify this release as client-only or server-only.
What else does Harium-mc1.20.1-2.0-cumulative-hotfix-v2.jar need?
Harium-mc1.20.1-2.0-cumulative-hotfix-v2.jar. Change the file and its required mods may change too.
This file does not list any required mods. Do not add a library just because a different file uses it.
This file does not list any required or optional mods.
Before you install it
Add Harium without breaking your instance.
Built for Harium-mc1.20.1-2.0-cumulative-hotfix-v2.jar. Pick another file and the loader, install side or required mods may change.
- 01
Stick to this file
Use Harium-mc1.20.1-2.0-cumulative-hotfix-v2.jar. It targets 1.20.1 with Forge; another release may have different loader, side or dependency requirements.
- 02
Bring the mods it needs
This file does not list any required mods. Do not add a library just because a different file uses it.
- 03
Put it on the correct side
The project page does not say whether this file belongs on the client, dedicated server, or both.
- 04
Pick the file you checked
Use the “Get this file” button beside Harium-mc1.20.1-2.0-cumulative-hotfix-v2.jar. It opens that exact file at the source.
About this project
What does Harium add?
Harium | General Purpose Optimization
Smart Performance Through Intelligent Code Replacement
What Is Harium
Harium is a general-purpose optimization mod (based on Lithium) that rewrites inefficient vanilla code with faster, smarter implementations — without changing game behavior.
Same Game. Better Performance.
Harium targets the most CPU-intensive systems in Minecraft: entity processing, redstone, AI, hoppers, and physics — replacing slow algorithms with optimized alternatives that produce identical results.
Optimization Categories
Each category can be individually enabled or disabled.
- AI & Pathfinding: Faster block type lookups, optimized POI searches, removed useless behaviors
- Entity System: Section-based movement tracking, optimized collision detection, smarter item merging
- Block & Redstone: Optimized redstone wire power calculations, BlockEntity sleeping for inactive tiles
- Hopper & Inventory: Event-driven hopper logic with caching — hoppers only scan when inventories actually change
- Memory Allocations: Eliminates unnecessary object creation in hot code paths using FastUtil collections
- VoxelShapes: Specialized shape implementations for faster collision detection and ray tracing
- Collections: Replaces standard Java collections with optimized FastUtil alternatives throughout
Key Technical Approaches
- Event-Driven Architecture: Block sections notify listeners only when changes occur, instead of polling every tick
- Caching Layers: Multiple levels of caching for block states, entity positions, and inventory contents
- Smart Iteration: Chunk-ordered entity iteration for better CPU cache locality and early termination
- Reduced Locking: Array-based data tracker entries instead of synchronized maps
Fork Information
Harium is a fork of Lithium by jellysquid3.
Compatible: Designed to be fully compatible with vanilla behavior. No gameplay changes.
Credits & Support
Original Lithium created by jellysquid3 and maintained by the community.
Harium extends the optimization coverage with additional improvements.
Join the Community
Get help and updates on our Discord.
Harium - Maintained by Hari - High Performance Minecraft
Project description from CurseForge.
Pick your setup
Harium by Minecraft version and loader
Choose the version and loader you play, then open the matching release.
Check the dependencies, then try the file in a copied instance before changing a world you care about.
Recent files
Harium versions and loaders
Harium-mc1.20.1-2.0-cumulative-hotfix-v2.jar
20 Aug 2026
Harium-mc1.20.1-2.0-projectile-quark-hotfix.jar
14 Aug 2026
Harium-mc1.20.1-2.0-pactched-v5.jar
10 May 2026
Harium-mc1.20.1-2.0-patched-v3.jar
6 May 2026
Harium-mc1.20.1-2.0-patched.jar
6 May 2026
Harium-mc1.20.1-2.0.jar
4 May 2026
Harium-mc1.20.1-1.0.0.jar
16 Mar 2026
Harium-mc1.20.1.jar
24 Jan 2026
Harium-Compat.jar
20 Jan 2026
harium-forge1.20.1-0.13.1.jar
30 Dec 2025
harium-forge1.20.1-0.13.jar
29 Dec 2025
harium-forge-1.20.1-v0.12.9hotfix.jar
29 Dec 2025
Looking for an older file? The official CurseForge project page is in Resources.