Minecraft Java
Minecraft Bedrock
PaperMC
Fabric
Forge
GeyserMC
Terraria
Factorio
Hytale
Discord bots
Quick answer
- Install Fabric API, then Lithium (game logic) and FerriteCore (memory). These two are safe for almost every server.
- Add Chunky to pre-generate the world and Spark to profile lag.
- Consider C2ME and ModernFix if you have several CPU cores or a big modpack.
The mods#
| Mod | What it improves | Needed on client? |
|---|---|---|
| Lithium | Game logic: mob AI, block entities, chunk and entity handling. | No |
| FerriteCore | Memory use, especially with many block states and mods. | No |
| ModernFix | Startup time and memory for big modpacks. | No |
| C2ME | Chunk generation and loading across multiple threads. | No |
| Chunky | Pre-generate chunks so exploring doesn't lag. | No |
| Spark | Profiler: finds what slows the tick. | No |
Lithium#
Lithium rewrites many small parts of Minecraft's game logic to do the same work with less processing, without changing how the game plays. It is the first mod to install on any Fabric server.
FerriteCore#
Minecraft stores a lot of duplicate data for blocks and models. FerriteCore shares it, which lowers memory use. That matters on a server with a fixed amount of RAM, where less memory pressure means fewer garbage-collection pauses.
ModernFix#
Targeted at large modpacks. It cuts launch time and memory by changing how resources load. A small vanilla-plus server may not see a big difference.
C2ME#
Spreads world generation and chunk loading across CPU threads. It helps most on servers that generate lots of new terrain. It changes how chunks are processed, so back up your world first and test with your other mods.
Chunky#
Run a pre-generation job for the area around spawn while the server is quiet. After that, players who explore load chunks from disk instead of generating them live, which removes most exploration lag spikes.
chunky world world
chunky center 0 0
chunky radius 3000
chunky startSpark#
Spark doesn't speed anything up by itself. It tells you why the server is slow. Run /spark profiler start, play for a few minutes, then /spark profiler stop and open the report link. See our TPS guide for how to read the results.
How to install them#
- Use Fabric
Create a Fabric server. On FreeGameHost choose Fabric when you create the server.
- Open Add-ons & Packs
Search for the mods by name. The panel picks files that match your Minecraft version and installs them in the
modsfolder. Install Fabric API first. - Restart
Restart the server and watch the console for errors.
- Test
Join, play, and run Spark. If something breaks, remove the last mod you added.
Always match the mod to your exact Minecraft version. A mod built for another version either won't load or will crash the server on start.
Also reduce the load from settings#
Mods help, but settings are free. Lower view-distance and simulation-distance in server.properties (see every setting explained), and keep entity farms and hoppers in check. The lag guide has the full checklist.
Mods to be careful with#
- Old lighting mods. Replacements from older versions can corrupt chunks or fail to load on new ones. Use only versions built for yours.
- Many overlapping optimisers. Install in small groups and test. More is not always better.
- Anything without a release for your version. Don't use a mod "for a nearby version".
Frequently asked questions#
Which Fabric mods improve server performance the most?
Lithium gives the biggest general gain (game logic, mob AI, chunk handling). FerriteCore cuts memory use. C2ME speeds up chunk generation and loading on servers with several CPU cores.
Do players need to install these mods?
No. These are server-side optimisations. Players can join with an unmodified game. Mods that add content are different and may need to be installed by players too.
Is it safe to use all of them together?
Lithium, FerriteCore and ModernFix are commonly used together. Add others one at a time and test, because overlapping mods can conflict or change behaviour.
Which mod pre-generates the world?
Chunky generates chunks in advance, so players exploring don't cause lag spikes. Run it while the server is quiet.
How do I find out what is actually causing lag?
Install Spark and run /spark profiler. It shows which tasks use the most tick time so you fix the real problem instead of guessing.
Do these work on every Minecraft version?
Mods are built per Minecraft version. Before installing, check each mod's Modrinth page lists your exact version, and use matching Fabric Loader and Fabric API versions.
