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.)
- Edition: Minecraft Java
- File type: .jar
- Minecraft version listed: 26.2
- How to install: Install the matching mod loader (Forge, Fabric or NeoForge) for your Minecraft version. → Download the .jar. → Put it in the .minecraft/mods folder and launch that loader profile.
- Where to get it: Opens on Modrinth — not every file is mirrored on our own servers.
Install steps are the general flow for this file type — How to install Minecraft Java mods & modpacks walks through it step by step.
- Ships as BadOptimizations-2.4.1-26.2-fabric.jar — drop this file into the mods folder
- Download size: 59 KB
- Download link checked 9 Sept 2026 — working
These come from our own check of the pack file, not from the source page.