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BadOptimizations

Optimization mod that focuses on things other than rendering

22.9M downloads
Created Apr 9, 2026
by thosea

About

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BadOptimizations

A collection of mostly micro optimizations that add up to something bigger!

What does it do?

Multiple things:<p>

  • Avoid updating lightmap<p> 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<p> 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)<p> 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.
<p> That's a few of them, at least. You can disable any optimization in the config file if you need to. </p>

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:<p> Without toasts, it goes from 1926-1955 FPS:<p> <img src="https://raw.githubusercontent.com/imthosea/images/refs/heads/master/badoptimizations/v1/image1.png" width="400"><p> To 2008-2023 FPS:<p> <img src="https://raw.githubusercontent.com/imthosea/images/refs/heads/master/badoptimizations/v1/image2.png" width="400"><p> And with toasts, it goes from 1351-1384 FPS:<p> <img src="https://raw.githubusercontent.com/imthosea/images/refs/heads/master/badoptimizations/v1/image3.png" width="400"><p> To 1414-1458 FPS:<p> <img src="https://raw.githubusercontent.com/imthosea/images/refs/heads/master/badoptimizations/v1/image4.png" width="400"><p>

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.)

Versions

v2.4.1Latest
1.21.11fabric, neoforgeDec 16, 2025

Version 2.4.1: - Migrate to Mojang Mappings - Change some comments in the config file - Update to 1.21.11 - Sky color is now data driven making sky color caching infeasible so it's been removed - Lightmap caching remains but no longer directly uses time as a factor, so lightmap_time_change_needed_for_update no longer has any effect - These changes don't apply to 1.21.10-

Download

Download

Download v2.4.1

Minecraft: 1.21.11

Loaders: fabric, neoforge

Tags

fabricforgeneoforge1.21.71.21.81.21.91.21.101.21.11