FerriteCore — a Mod to Reduce RAM Usage in Minecraft

FerriteCore — a Mod to Reduce RAM Usage in Minecraft

FerriteCore is a technical mod that reduces RAM usage in Minecraft without affecting gameplay in any way. The game keeps a large amount of internal data about blocks and their models in RAM, and some of this data is either duplicated or stored inefficiently. The mod rewrites exactly these areas: it merges identical structures and stores them in a more compact form, so the same set of mods takes up less memory.

What the mod does

FerriteCore doesn't add any game content and has no interface — it works in the background from the very first launch. All the mod's work happens at the level of how the game engine stores internal data in memory. The optimizations cover two sides: some work only on the client (everything related to models and rendering), and some work on both the client and the server (block state data, shape cache, chunk loading).

No commands or manual actions are needed after installation: the default settings immediately enable all the key optimizations. The actual savings depend on the specific modpack — the more mods with complex blocks and models it has, the bigger the gain.

What causes the memory reduction

The mod doesn't rely on a single trick — it's a set of separate optimizations, each of which removes its own category of redundant data. Below are the main ones, with figures from the developer's own tests (the exact savings depend on the modpack).

• Block states. The biggest expense. To quickly find "neighboring" states of a block (for example, the same block with a different direction or level), vanilla builds a separate table for each block. On complex blocks these tables grow and take up around 600 MB. The mod replaces them with a more compact structure that produces the same result through a few arithmetic operations.

• Block models. For blocks with multipart models, vanilla creates a separate copy of the model and its display conditions for every single block state — resulting in tens or hundreds of thousands of nearly identical objects. The mod caches identical conditions and reuses identical models, cutting their number down to a few thousand.

• Collision and render shapes. Many blocks share the same collision and rendering geometry. Instead of storing it separately for each state (around 200 MB), the mod keeps a single copy of the shared shape.

• Chunk loading (server). While a chunk goes through its loading stages, vanilla keeps the full set of its data in memory. The mod leaves only the necessary subsections (entities and block entities) at the intermediate stage, freeing up 90–100 MB.

Settings

The configuration lives in the file ferritecore-mixin.toml. All the main optimizations are enabled by default, so most players will never need to open this file. The remaining parameters are individual toggles for each optimization, and it's best to leave them as they are. There are really only a few options worth touching:

Conclusion

FerriteCore significantly reduces the amount of RAM Minecraft spends on internal data, and it does so with virtually no impact on performance during gameplay. Its main limitation is that the mod saves memory, not frames: don't expect a noticeable FPS boost from it. It provides the most benefit in heavy modpacks, on servers, and on PCs with limited RAM, where a memory buffer directly affects stability.