Warning
In 26.1 Minecraft changed how mod developing works. There are no more yarn mappings which are required for this mod. I could try to make a new version but I still think that a lot of people are on 1.21.11 so I won't do it for at least a month while I learn the new offical mappings. I hope you have an understanding for this.
Rhenium
Rhenium is a Fabric performance optimization mod designed to reduce lag in large survival worlds, particularly those with complex redstone contraptions and automated storage systems.
What it optimizes:
- Hopper throttling — Idle hoppers that have nothing to move are throttled, significantly reducing tick overhead in large storage systems with many hoppers
- Item entity throttling — Stationary ground items tick less frequently, reducing lag in areas with large item piles
- Chest render culling — Chest block entity renderers are skipped beyond 24 blocks, reducing client FPS drops in storage rooms with many chests
- Particle culling - Changes the distance at which the particles are rendered
- Entity culling - Changes the distance in which the entities are rendered
Fully configurable — Every optimization can be toggled individually via Mod Menu, so you keep only what you need.
Requirements:
- Fabric Loader 0.16.10+
- Minecraft 1.21.1 – 1.21.11
- Mod Menu
- Cloth Config
Recomended mods:
- Sodium
- Lithium
- Entity culling
Questions
If you have any questions not explained in the description, feel free to join my discord server!

- Edition: Minecraft Java
- File type: .jar
- Minecraft versions listed: 1.21.1, 1.21.2, 1.21.3
- How to install: Install the matching mod loader (Forge, Fabric or NeoForge) for your Minecraft version. → Download the .jar. → Put it in the .minecraft/mods folder and launch that loader profile.
- Where to get it: Opens on Modrinth — not every file is mirrored on our own servers.
Install steps are the general flow for this file type — How to install Minecraft Java mods & modpacks walks through it step by step.
- Ships as rhenium-1.2.0+mc1.21.11.jar — drop this file into the mods folder
- Download size: 48 KB
- Download link checked 1 Sept 2026 — working
These come from our own check of the pack file, not from the source page.
