
Hydrogen
Reduces the memory usage of the game in more modded scenarios
About this Mod
Status
January 23rd, 2022
This repository has been archived as we do not have the time or resources needed to maintain the project. No further updates will be published, and we won't be providing help for using it.
If you are looking for a replacement, consider taking a look at FerriteCore, as it generally offers more significant improvements to memory usage in modded scenarios and is currently available for the latest version of Minecraft.

Memory usage before and after installing Hydrogen into the popular All of Fabric 3 modpack.
Hydrogen is a free and open-source mod designed to reduce the game's memory requirements by implementing more memory-efficient data structures and logic. It's primarily designed for more heavily modded scenarios, but can offer (small) improvements even in lightly modded or vanilla scenarios.
The mod works on both the client and server, and doesn't require the mod to be installed on both sides. However, the benefits of running Hydrogen on the server are pretty small as of the moment.
Features
Implements more compact data structures for block states and properties, reducing memory usage significantly when using mods that add lots of complex blocks
De-duplicates block model geometry, saving memory on the client when multi-part block models are used
Fixes a few leaks in chunk loading code that results in the NBT data on disk being kept in memory after a chunk has loaded
Simplifies and flattens block model predicates to reduce unnecessary chaining
Available Versions
How to Install Hydrogen on Your Server
Order Server
Order a Minecraft Java server with at least 3 GB RAM (4 GB recommended).
Set fabric Loader
In the panel under "Egg", select the fabric loader and matching Minecraft version (1.17.1).
Install Mod
Open the mod browser in the dashboard and search for "Hydrogen". Click "Install" – done! Alternatively, upload the .jar via SFTP to the /mods folder.
Compatibility
Mod Loaders
Minecraft Versions
1.17.1, 1.17, 1.16.5
Server-side
~ OptionalRecommended RAM
4 GB(min. 3 GB)Frequently Asked Questions
Hydrogen server crashes on startup – what to do?
Most common cause: wrong fabric version or insufficient RAM. Check the server log (latest.log) for "OutOfMemoryError" or "Mixin" errors. With Mado Hosting: ensure at least 3 GB RAM is allocated and the loader matches the mod version (1.17.1). You can switch loaders with one click in the panel.
Is Hydrogen compatible with fabric?
Hydrogen officially supports fabric for Minecraft 1.17.1, 1.17, 1.16.5. The Mado dashboard automatically detects incompatible loader combinations.
Server lagging with Hydrogen – how to optimize performance?
Recommended RAM: 4 GB (per 8 players). Use /spark profiler to check if Hydrogen consumes the most tick time. Common fixes: reduce server view-distance to 8-10, install "performant" or "starlight" as supplementary mods on Forge. With Mado Hosting, your server runs on NVMe SSDs with dedicated CPU cores for minimal latency.
Similar Mods
Rent Modded Server
Install Hydrogen with just one click on your server.