
Uranium (Lag)
The fastest and most compatible lag mod for Minecraft. Now available for both Forge and Fabric!
Screenshots

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
How to Install Uranium (Lag) on Your Client
Install the Mod Loader Locally
Install fabric for your local Minecraft version.
Download the Matching File
Choose the Uranium (Lag) file for fabric and Minecraft 1.20.6.
Install Mod
Place the .jar file in your local .minecraft/mods folder and restart Minecraft. No server-side installation is required.
Compatibility
Mod Loaders
Minecraft Versions
1.20.6, 1.20.5, 1.20.4 (+4 more)
Server-side
✗ UnsupportedRecommended 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.
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Minecraft Server for Your Group
Uranium (Lag) stays on your client. Host a compatible world for your group.