Experimental Performance
by PedrixzZ
Experimental Performance is a Fabric optimization mod for Minecraft 1.20.4 that reduces the memory footprint of some of the game's core classes.
What it does
The mod targets memory layout. Several of Minecraft's classes are large, and a single instance can take up more bytes than a processor cache line holds, so one operation may need several cache loads. Experimental Performance splits the fields of the chunk, block and entity classes so that each instance fits into fewer cache lines, and it reports this as a set of separate optimizations. The author says the chunk change brings the class down to 64 bytes on some computers, where most chunk operations run about 0.25x faster. The block change moves data into a smaller BlockInfo class, and the entity class, which is 272 bytes, is still being reduced.
The mod is published for Fabric only, with a single file, 0.1.1, for 1.20.4, dated 2023-12-28 on the beta channel. Fabric API is needed to run it. Experimental Performance is open source under the Apache License 2.0. Either side can run it, and neither needs it, so it can run on a single player client, on a dedicated server, or on both. The author notes that some changes use fabric-ASM, which can conflict with other mods that modify the same classes, and that compatibility with other mods is still being worked on.
Key features
Chunk memory layout
The chunk class is trimmed from about 80 bytes toward 64 bytes, so it fits a single processor cache line on suitable hardware.
Block memory layout
Block data is moved into a BlockInfo class, which reduces the weight of the block class from 72 bytes.
Entity memory layout
The entity class, at 272 bytes, is reduced over several steps, and the author plans a rewrite that provides an API for it.
Bytecode edits
Some changes use fabric-ASM to rewrite variables and redirect calls in the chunk class, instead of changing its source.
Compatibility
Latest build for each game version and loader.
Only full game releases are shown. This mod publishes no snapshot builds.
How it compares
Hydrogen is a Fabric mod for 1.16.5 – 1.17.1 that is open source under the GNU Lesser General Public License v3.0 only. Either side can run it, and neither needs it, so it targets an earlier release range. Redirected is open source under the GNU Lesser General Public License v3.0 only, is published for Fabric, Forge and NeoForge across 1.20 – 1.21.1, and is client and server, so both sides need it. Netty Memory Tweaker is client-side only under the Mozilla Public License 2.0 and is not open source, for 1.20.6 – 1.21.
| Mod | Loaders | Game versions | Environment | Updated |
|---|---|---|---|---|
| Experimental Performance | Fabric | 1.20.4 | Client or server, optional | 2023-12-28 |
| Hydrogen | Fabric | 1.16.5 – 1.17.1 | Client or server, optional | 2021-07-15 |
| Redirected | Fabric, Forge and NeoForge | 1.20 – 1.21.1 | Client and server | 2025-02-02 |
| Netty Memory Tweaker | Fabric | 1.20.6 – 1.21 | Client-side only | 2024-06-15 |
Questions
Does Experimental Performance require Fabric API?
Does the server need the mod?
Which game version is supported?
In the catalog
Experimental Performance is one of 3,545 Optimization mods on ModsFinder, and one of 2,575 Optimization mods for Fabric. 13,907 mods support Minecraft 1.20.4.
Similar mods
What the author says
Memory Allocation Some classes can be very memory dense, they have a big memory footprint. This is an issue because your computer can only fit 64 bytes into a processor's cache line, so anything over 64 needs to be split into multiple lines. This can drastically slow down operations based on what is being called. So…
Official listing
- Modrinth page
- modrinth.com/mod/experimentalperformance
- Owner
- PedrixzZ
- Published
- 2023-12-28
- Updated on Modrinth
- 2023-12-28
- Facts verified
- 2026-10-15