CurseForge · Minecraft mod
BadOptimizations
Optimization mod that focuses on things other than rendering
Quick answer
Which BadOptimizations release matches 26.1.2 Fabric?
BadOptimizations 2.4.1 (26.1-26.1.2/fabric) targets 26.1, 26.1.1, 26.1.2 with Fabric. The project page does not say whether it belongs on the client. The project page does not say whether it belongs on the dedicated server. No extra mods listed for this file.
Where it goes
Is BadOptimizations required on the client, server, or both?
The project page does not say whether it belongs on the client. The project page does not say whether it belongs on the dedicated server.
The source does not explicitly classify this release as client-only or server-only.
What else does BadOptimizations 2.4.1 (26.1-26.1.2/fabric) need?
2.4.1 (26.1-26.1.2/fabric) on 26.1.2 Fabric. Every mod below is checked against that same setup.
This file does not list any required mods. Do not add a library just because a different file uses it.
This file does not list any required or optional mods.
Before you install it
Add BadOptimizations without breaking your instance.
Built for BadOptimizations 2.4.1 (26.1-26.1.2/fabric) on 26.1.2 Fabric. Pick another file and the loader, install side or required mods may change.
- 01
Stick to this file
Use 2.4.1 (26.1-26.1.2/fabric). It targets 26.1, 26.1.1, 26.1.2 with Fabric; another release may have different loader, side or dependency requirements.
- 02
Bring the mods it needs
This file does not list any required mods. Do not add a library just because a different file uses it.
- 03
Put it on the correct side
The project page does not say whether it belongs on the client. The project page does not say whether it belongs on the dedicated server.
- 04
Pick the file you checked
Use the “Get this file” button beside 2.4.1 (26.1-26.1.2/fabric). It opens that exact file at the source.
About this project
What does BadOptimizations add?
BadOptimizations
A collection of mostly micro optimizations that add up to something bigger!
What does it do?
Multiple things:
- Avoid updating lightmap
Updating lightmap textures are one of the most expensive parts of the client tick. During each tick, the client will do vector math to calculate lightmaps for blocks and the sky, then upload that new texture to the GPU. However, this can be completely avoided and cached if nothing affecting block brightness has changed. This mod will cancel lightmap updates if nothing that changes block brightness (e.g. gamma slider, potion effects, dimension) has changed. - Don't do debug logic if we don't need to
Minecraft has four debug renderers that can be activated with a debug server: bees, game events, game test and villager AI. Even if there's nothing to process, the logic for these debug renderers are still executed. This mod will only execute them if debug is enabled and there is data from the server to process. - Sky color calculation optimizations (1.21.10 and below)
Minecraft uses a cubic color sampler every frame to calculate the current sky color. This function loops 216 times to factor in surrounding biomes, even if all surrounding biomes are identical or have identical sky colors. This mod makes the color sampler only used if you are between biomes with different sky colors, and caches it for each tick. Otherwise, a shorter, simpler and faster sky color calculation is used.
That's a few of them, at least. You can disable any optimization in the config file if you need to.
How much does it help?
Depends on your system and luck, but on my own PC, an RTX 3060, intel i7 12700 and 4GB of allocated ram on Fabulously Optimized:
Without toasts, it goes from 1926-1955 FPS:

To 2008-2023 FPS:

And with toasts, it goes from 1351-1384 FPS:

To 1414-1458 FPS:

My mod is incompatible!
You can mark your mod as incompatible with specific BadOptimizations options. If your mod is present, BadOptimizations will automatically disable the specific options you specify.
You can also add hooks that tell BadOptimizations when the lightmap or sky color needs to be updated instead of adding a hard incompatibility to the caching optimizations.
Dependencies?
None.
(Also available on CurseForge, if that's your thing.)
Project description from CurseForge.
Pick your setup
BadOptimizations by Minecraft version and loader
Choose the version and loader you play, then open the matching release.
26.1.2
2 loader builds26.1.1
2 loader builds26.1
2 loader builds1.21.11
2 loader builds1.21.10
2 loader builds1.21.9
2 loader builds1.21.8
2 loader builds1.21.7
2 loader builds1.21.6
2 loader builds1.21.5
2 loader builds1.21.4
2 loader buildsShowing the newest 12 of 26 game versions. Older files are in the list below.
Check the dependencies, then try the file in a copied instance before changing a world you care about.
Recent files
BadOptimizations versions and loaders
2.4.1 (26.1-26.1.2/fabric)
BadOptimizations-2.4.1-26.1-fabric.jar
29 Mar 2026
Looking for an older file? The official CurseForge project page is in Resources.