Faster Random

Faster Random has been archived as of 2025-12-27, and has not been publicly updated in over a year.

This is because I've both heard of and gotten far too many conflicting results about this mod's performance, and feel as though this mod should not be relied on as a result. Any performance gain you notice could potentially just be a placebo effect (especially since your JVM may force the mod to disable itself!), or may outweight the impacts to vanilla parity on your world.

This arises from the fact that the generator is dependent on specific conditions arising to noticably beat Minecraft's generators, and I don't think random functions occupy enough CPU time to make any increase apparent. I really don't have any idea of if this makes a big server run meaningfully faster or not at this point, and my system may be too bottlenecked to know.

Consider this to be only reccomended for use with worlds that previously were generated with Faster Random, to keep parity. This will be the only form of support provided. The potential for 'some' gain isn't really worth losing vanilla parity.

TL:DR: On paper, Faster Random is faster in theory, but this is situational, and something that I haven't been able to reliably test.

Additional Findings

Oddly enough, my old findings of L64X128MixRandom being 2x slower than base, vanilla XoroShiro128++ on repeat constructions are not showing up anymore. I'm not sure if JDK's improved on this behaviour over time, but it is still situational (at the level of the player's actions, at least) even without the prior consideration.

Again, this finding is nowhere near enough to convince me that this mod is actually doing anything.

2024 Mod Description

Faster Random

Faster Random is a rewrite of Minecraft's random systems to use the new LXM generators introduced in Java 17, instead of the slower CheckedRandom (and related generators) within Minecraft. Most JVM's should support the generator by default, but check your logs for any warnings!

This also patches the MC-239059 "bug"(which doesn't have much of an effect on the game, but is still a bug.)

Faster Random's generators take more time to construct on most systems (I only have my Linux AMD system to go off of), but are much faster to generate numbers. Since minecraft re-uses many generators (meaning the construction penalty is avoided), the performance gain can vary largely.

Performance can be tested via the testmod, which runs a benchmark against each method when run.

Currently, Faster Random targets the slower random generators, which creates a performance boost with world structure placement/generation, and feature + carver placement and generation, alongside a lot of client-side things like dropped items. Currently Faster Random does not do anything to the faster generators yet. (Until I'm sure it'll improve performance noticably and not cause more harm than good)

Should you use this mod?

It's likely that Faster Random will only improve worldgen performance up to a certain extent, as you'll quickly hit a RAM and I/O bottleneck from the increased amount of chunks stored in RAM/being written to disk. This isn't a bad thing, this just means that you're generating chunks faster than the rest of your system can store them. Depending on your system, your mileage may vary greatly.

As a result, this mod provides the most performance in situations where the server thread(s) are CPU bottlenecked (singleplayer runs on an internal server), but have access to a decent amount of fast memory and storage (DDR4 RAM, and a SATA III or better HDD).

For world generation, Faster Random is almost 1:1, but some cave shapes will generate differently to Vanilla. Everything else is 1:1. It's likely that these differences will be unnoticiable, but shouldn't be used for parity-sensitive things like speedrunning. Optifine's math optimizations do far more damaging changes to worldgen than Faster Random.

Faster Random does not need to be on both the client and server. Faster Random can provide a small performance boost client-side, as quite a few things are still random there.

System Requirements (3.0.0+)

• A JVM that fully supports Java 17's new RandomGenerator system, and implementations of the LXM generators alongside it. (example: [GraalVM](graalvm.org )). Having an unsupported JVM will disable Faster Random, and will require you to use Faster Random 1.6.0. If your JVM doesn't support this, chances are it's not a good JVM.

(Note: You may be unknowingly using a headless JDK for Minecraft, which breaks Faster Random due to a variety of strange reasons. Please check if you have downloaded the correct JDK/Package if Faster Random is crashing.)

If you're using the normal Minecraft Launcher, this mod should work fine with the bundled JVM, and you're free to ignore these instructions if no warning shows up in your logs.

Usage with other mods

Faster Random should work well with a large variety of mods, especially after 4.0.0. Faster Random will also actively support most major worldgen mods and Distant Horizons.

Faster Random also can perform better alongside other terrain optimization mods such as Noisium and C2ME, thanks to them making better leverage of Minecraft's random systems with multithreading. Ideally, you should use Noisium + Faster Random, and throw as much ram (10GB+) as you can spare at Minecraft when using Distant Horizons (C2ME has a performance hit with DH). Faster Random can leverage Noisium for a reduction in CPU usage from world generation.

Forge?

**Francium** is an unofficial forge variant for 1.16 and 1.18, which mostly does what Faster Random does, albeit without the worldgen optimizations. For 1.20.1 and these worldgen changes, **Sinytra Connector** should be able to run the mod with a "stable enough" experience. For 1.20.1+, you can try using the NeoForge port.

Faster Random's Icon is licensed under CC-BY-SA. Code is licensed under Apache 2.0.

Like this mod? Feel free to support development by contributing code, creating bug reports, and letting others know about it (it helps a lot)!