Fast Noise – Faster World Generation with Vanilla Parity V3.4.0

Features:

• Speeds up world generation
• Keeps vanilla parity in generated worlds
• Vanilla parity holds with datapacks too
• Around 10-18% faster overworld generation
• Much larger gains in the Nether and the End
• Rewrites the noise biome and surface generation steps
• Fewer memory allocations and no palette resizing
• Block counting delayed and packed together
• Caches block state data and precalculates values
• Optimizations that may affect mod compatibility are off by default
• Fabric and Quilt support
• For Minecraft 1.21.1

Fast Noise is an optimization mod aimed squarely at how long Minecraft takes to generate a world. Chunk generation is one of the heaviest jobs a server or a single player world does, and this mod attacks it directly while keeping vanilla parity, so the terrain you get is the terrain you would have got anyway, datapacks included. Only the general non-determinism that vanilla already has applies.

The speedup comes from how block and biome data is stored into chunks during generation. The mod replaces the noise population, biome population and surface building steps with tighter, more packed versions of the same work: far fewer allocations, no palette resizing while a chunk fills up, block counting delayed and batched instead of done constantly, data precalculated ahead of time and block state information cached rather than looked up over and over.

In practice that works out at roughly 10 to 18 percent off overall overworld generation on recent versions, with much bigger gains in the Nether and the End. Measured stage by stage, the surface and noise steps show the largest speedups there, and both pre-generation runs and micro-benchmarks were used to check the numbers.

Compatibility is treated carefully. Only code that is safe to touch gets modified, and the specific optimizations that could affect mod compatibility are disabled out of the box, so custom worldgen mods can be used alongside it. At 0.04 MB it is about as small as a mod gets, and it runs on Fabric and Quilt for Minecraft 1.21.1.