Mod Hydrogen

Hydrogen, memory optimization for modded Minecraft

Hydrogen is an open source Fabric mod for Minecraft Java Edition that targets memory use in heavily modded setups. It replaces inefficient data structures, deduplicates block model geometry, simplifies model predicates, and helps release chunk NBT data that could otherwise remain in memory. The result is a lighter memory footprint, with modest benefits possible in vanilla or lightly modded play and stronger gains in large modpacks.

Hydrogen is designed to be transparent, so it does not alter gameplay rules. It can run on the client or server, although client benefits are generally more noticeable. It supports Minecraft 1.16.5 and 1.17.x, and has been archived since January 23, 2022. For a Minecraft server, BoxToPlay helps maintain compatible modded setups.