Minecraft Fabric: Performance mods

If your Fabric server is lagging, struggling with TPS drops, or using more RAM than it should, performance mods can help. These mods optimize how the game runs without changing gameplay, and most of them are server-side, so you can add them on top of an existing modpack.

Back up first. AleForge recommends making a backup of your server before installing any additional mods.

Recommended Performance Mods

Mod	What It Does
Lithium	A general-purpose optimization mod for Fabric. It rewrites many of the game’s internal systems (like AI, physics and block updates) to run faster, without changing how they behave. This is the mod most people should install first.
FerriteCore	Reduces the amount of RAM Minecraft uses by making its memory usage more efficient. Great for servers that are running close to their memory limit.
Memory Leak Fix	Fixes several known memory leaks in the base game, so your server’s memory use stays stable over long uptimes instead of slowly climbing.
Krypton	Optimizes Minecraft’s networking code, so the server can handle packets more efficiently. Most useful on servers with a lot of players.
DynamicView	Automatically lowers the server’s render distance when TPS drops, then raises it again once performance recovers. Helps keep the server playable during lag spikes instead of crashing or freezing.
LazyDFU	Speeds up server startup time by delaying unnecessary data-conversion work until it’s actually needed. Note: Mojang built most of this improvement into the game itself starting in Minecraft 1.19.4, so LazyDFU mainly helps on older versions now.

How to Install

You can install these mods in two ways. Option A is the easiest.

Option A: Install from the Panel (Depot)

1. Log in to your panel and open your server.
2. Open the Depot section.
3. At the top, open the Mods section.
4. In the filter, select your server’s Minecraft version. Use the exact version your server is running, so you only see mods that are compatible.
5. Find the mod you want (for example, Lithium or FerriteCore) and click Install.
6. Repeat for each mod on this list that you want to add.
7. Restart your server so the mods load.

This installs the mod with one click, in the right version for your server, without you needing to download or upload anything yourself.

Option B: Upload the Files Manually

1. Download the correct mod version for your Minecraft version and mod loader (Fabric) from Modrinth or CurseForge.
2. Back up your server.
3. Stop the server.
4. Open the File Manager and go into the mods folder.
5. Upload the .jar file for each mod.
6. Start the server and check the console to make sure every mod loaded without errors.

Install mods one at a time if you can, and restart between each one. This makes it much easier to tell which mod is responsible if something goes wrong.

A Few Tips

• Match your Minecraft version. Always download the build made for your exact server version.
• You don’t need every mod on this list. Lithium and FerriteCore give the biggest general improvement for most servers. Add the others based on the specific problem you’re trying to fix, like memory leaks or too many players.
• Test after each change. Performance mods are generally safe, but conflicts between mods can happen. Keep an eye on your console log and your TPS after installing anything new.