Uranium (Lag)

Uranium (Lag)

The fastest and most compatible lag mod for Minecraft. Now available for both Forge and Fabric!

by
973 Downloads
fabricforgecursedoptimizationutility
Configure a Compatible Minecraft Server

Screenshots

F3 screenshot with the mod on

About this Mod

Introducing Uranium, a mod designed to take your Minecraft experience to a new level of challenge by introducing intentional lag. This mod makes the game unplayable, testing your patience and resilience.

Uranium was originally created as a joke to show friends how Minecraft used to run on my PC. Instead of describing bad performance, this mod recreates it by deliberately wasting processing power to cause lag, stuttering, and extremely low FPS.

The mod does not add new gameplay content, blocks, or items. It does not modify visuals, collect data, or perform any malicious actions, it simply makes the game run worse on purpose. The full source code is publicly available for transparency.

Uranium is intended for humor, experimentation, and challenge scenarios, such as joke modpacks or patience tests.

Available Versions

Uranium (Lag) 0.1-1.20release
MC 1.20, 1.20.1, 1.20.2, 1.20.3, 1.20.4, 1.20.5, 1.20.6forge
January 4, 2026
Uranium (Lag) 0.1-1.20.1release
MC 1.20, 1.20.1, 1.20.2, 1.20.3, 1.20.4, 1.20.5, 1.20.6fabric
January 4, 2026

How to Install Uranium (Lag) on Your Client

1

Install the Mod Loader Locally

Install fabric for your local Minecraft version.

2

Download the Matching File

Choose the Uranium (Lag) file for fabric and Minecraft 1.20.6.

3

Install Mod

Place the .jar file in your local .minecraft/mods folder and restart Minecraft. No server-side installation is required.

Compatibility

Mod Loaders

fabricforge

Minecraft Versions

1.20.6, 1.20.5, 1.20.4 (+4 more)

Server-side

Unsupported

Recommended RAM

4 GB(min. 3 GB)

Frequently Asked Questions

Does Uranium (Lag) need to be installed on the Minecraft server?

No. Modrinth marks Uranium (Lag) as unsupported on the server side. Install it only in your local Minecraft mods folder. Your server can remain unchanged unless the mod page lists an additional dependency.

Which version and loader does Uranium (Lag) require?

Use a file for fabric, forge and your exact Minecraft version. Supported versions include 1.20.6, 1.20.5, 1.20.4. Files for different loaders are not interchangeable.

Uranium (Lag) is not working – what should I check?

First check the Minecraft version, loader version and required dependencies. Put the .jar file in your local .minecraft/mods folder and remove older duplicates. Because this mod is client-side, adding server RAM will not fix it.

Minecraft Server for Your Group

Uranium (Lag) stays on your client. Host a compatible world for your group.

Recommended RAM
4 GBfrom €5.2/mo
Minimum 3 GB | per 8 players
Create Server Now
Client Compatibility Guide
NVMe SSD Storage
DDoS Protection included

Details

License
LicenseRef-All-Rights-Reserved
Server-side
Unsupported

Supported Versions

1.20.61.20.51.20.41.20.31.20.21.20.11.20