Screenshot 1 of 5. C2ME benchmark chart comparing chunk generation throughput against Paper and vanilla Minecraft from 2 to 96 threads
What C2ME works with.
| Platform | Java Edition |
|---|---|
| Loaders | Fabric |
| Minecraft versions | 1.17.1, 1.18.2, 1.19.4, 1.20.6, 1.21.11, 26.1.2, 26.2, 26.3 |
| Environment | Client, Server |
C2ME, short for Concurrent Chunk Management Engine, is a Fabric mod that spreads chunk generation, I/O and loading across multiple CPU cores. Fabric builds cover Minecraft Java 1.17.1 through 26.3. It is required on the server and optional on the client. The trade-offs are plain: it ships for Fabric only here, and the newest builds are alpha.
What C2ME changes
C2ME takes advantage of multiple CPU cores in parallel to improve chunk generation, I/O and loading, and it is about making world generation and chunk I/O more scalable. The creator's latest benchmarks run from 2 to 96 threads on 26.2 with the Terratonic and Terralith datapacks, with globalExecutorParallelism in c2me.toml set to the thread count.
C2ME does not alter vanilla world generation by default. Vanilla generation is itself non-deterministic, so worlds vary run to run even with the same seed. That is not a C2ME bug.
Installation
Install Fabric Loader for the same Minecraft release as your C2ME file. Put the C2ME jar in the mods folder (.minecraft/mods by default), then launch the Fabric profile. A dedicated server needs it. On the client it is optional. The newest build requires no other mod.
Versions and support
- Minecraft Java: 1.17.1 to 26.3. The ceiling build is 0.4.2-alpha.0.88+26.3, published September 24, 2026.
- Full support: only the latest release and latest snapshot. Older releases get critical fixes only, and older snapshots get none.
- Dependencies: none required.
Compatibility and companions
For performance, the creator recommends running C2ME with Lithium and ScalableLux. World generation datapacks that run on vanilla are fully supported. Mods that add their own world generators usually work, but some break assumptions that C2ME relies on for speed. C2ME also includes checks that flag mods misusing world random. Take those reports seriously and send them to the mod author.
See C2ME in action
C2ME demonstration showing faster chunk loading
Questions about C2ME.
5 questions
Which Minecraft versions does C2ME support?
The Fabric builds run from Minecraft Java 1.17.1 to 26.3. Only the latest release and latest snapshot are fully supported. Older releases are in long-term support and get critical bug fixes only, and older snapshots are not supported.
Does C2ME need Fabric API?
No. The newest build lists no required dependencies, so Fabric Loader and the C2ME jar are enough. The creator recommends adding Lithium and ScalableLux alongside it for performance.
Do I need C2ME on the client and the server?
It is required on the server and optional on the client. Installing it on the client is not required to join a server that runs it.
Does C2ME work on Forge, NeoForge or Paper?
These builds are for Fabric only, and a Java mod loads only with the loader its build was made for, so they will not load on Forge. Paper appears in the creator's benchmarks only as a comparison point.
Is C2ME stable?
The newest builds are alpha, so expect rough edges. C2ME aims to keep vanilla behaviour and does not change world generation by default, but the creator still advises backing up worlds and reporting any deviation on the issue tracker.
