The best server side performance mods for a Fabric Minecraft server

None of these mods adds blocks, items or mobs, so a player with a plain game or another set of client mods can still join.

Lithium rewrites parts of the game logic: how mobs find paths, how entities collide, how blocks and chunks tick, how hoppers search for items. The aim of the project is the same result as the normal game, done faster.

• Install it first on every Fabric server. It gives the largest gain of the safe mods.
• It also exists for NeoForge.
• Each optimization can be switched off in config/lithium.properties if a farm behaves differently. That is rare, and the mod's documentation lists the option names.

FerriteCore stores block states and models more efficiently. The saving is largest with many mods that add blocks, and it is felt on the memory graph of the Overview tab.

ModernFix shortens the start of the server and lowers memory use, mostly by loading things only when they are needed. A modpack that takes minutes to start often starts much sooner with it.

Both work on Fabric, Forge and NeoForge, and both are safe to combine with Lithium. Many modpacks already include them; check the mods folder in the Files tab before adding a second copy.

Two copies of the same mod, for example an old and a new FerriteCore jar, stop the server from starting. Remove the old file when you update.

C2ME, short for Concurrent Chunk Management Engine, spreads chunk generation, loading and saving over several processor cores. On a fresh world with players exploring in different directions, new land appears faster and the main thread has less to wait for.

• The gain is largest on new land. On a world that is already pre-generated, the effect is smaller.
• It changes deep parts of world generation. Mods that add their own terrain or structures can clash with it.
• Make a backup in the Backups tab before adding it to an existing world, and test it on a copy if the world matters.

C2ME is Fabric only. Its versions follow the Minecraft releases with some delay, so check that a release exists for your version.

Krypton optimizes the network code of the server: how packets are built, compressed and sent. The effect shows on servers with many players at once; for a few friends the difference is small. Mods that change networking themselves can clash with it, so test after installing.

Alternate Current replaces the way redstone dust updates its neighbours with a much cheaper method. Large redstone builds cost far less tick time. Most contraptions work the same, but some that depend on the exact update order can fire differently, so test the important farms.

1. Open the Mods tab of your Fabric server.
2. Type the name of the mod in Search mods under Verified Modrinth catalog and press Search. The catalog shows only stable server side releases for exactly your server type and Minecraft version.
3. Press Verify & install on the mod. When the mod needs another mod to run, the panel installs that one along with it.
4. Restart the server to load the mod.
5. Check the Console for errors during the start.

When a mod does not show up in the search, there is no stable server side release for your version yet. Wait for one, or check the mod page. Uploading a jar by hand in the Files tab works as well; install mods covers both ways.

Add one mod at a time and restart in between. When a start fails, you know which mod caused it.

Mods do not fix a world that is simply too busy. If spark still shows entities or hoppers at the top, look at reduce lag for the farms and settings behind it, and at view distance in server.properties.

No. These mods only change how the server does its own work. What the server sends to players stays the same, so players with the normal Fabric launcher, a modpack launcher or no mods at all can join.

Players can install some of them in their own game for better frame rates; Lithium, FerriteCore and ModernFix also work on the client. That is their own choice and has no effect on the server. Content mods are different: join a modded server explains which mods players must match.