A Minecraft performance mod for Apple Silicon Macs. Very much alpha: expect bugs, and back up your worlds.

Requirements

• An Apple Silicon Mac on macOS 26 or later
• Java 25
• Minecraft 26.3 with Fabric Loader 0.19.5
• Sodium 0.9.3, a separate download: sodium-fabric-0.9.3-alpha.1+mc26.3.jar

Install

Drop the mcopt jar and the Sodium jar into ~/Library/Application Support/minecraft/mods. Done.

Shows an fps counter in the top-left corner (hidden with F1 or F3).

Settings

• The perf profile is on by default and picks its settings for your Mac.
• profile=none in config/mcopt.properties turns it off. The first launch writes that file.
• Far terrain is an experimental opt-in: mcopt.lod=true in the same file, for Macs with 10 or more GPU cores.

Numbers

fps spinning / flying, same test world, 1920x1080, render distance 16, VSync off, two runs each:

Mac	previous build	0.2.0-alpha.1
Mac mini M4 (10-core GPU, 16 GB)	1094-1103 / 977-989	1072-1119 / 994-1002
MacBook Neo (A18 Pro, 5-core GPU, 8 GB)	379-449 / 324-339	460-471 / 415-432

Known issues

• Only Sodium 0.9.3 works. With another version, Fabric stops at launch and says which one to install.
• Mods that call OpenGL directly can't draw on the Metal backend. -Dmcopt.metal=false switches mcopt's renderer off.
• Distant Horizons only works on OpenGL. mcopt detects it and stays on OpenGL, so it runs without the Metal renderer's speedup; mcopt's other optimizations stay on. (0.2.0-alpha.1 crashed with it instead: add mcopt.metal=false to config/mcopt.properties there.)
• Far terrain is experimental. On Macs with fewer than 10 GPU cores, it costs most of the fps.
• With fewer than 10 GPU cores, or 8 GB of memory or less, the profile leaves out the bigger chunk cache.
• With Lithium, C2ME or ScalableLux installed, some of mcopt's chunk patches step aside on purpose.

Plans

• Far terrain on by default, with tiers for smaller Macs
• Our own shaders (BSL-level) as an option
• Faster world generation (native noise, bit-exact)
• More exact server-tick and chunk optimizations, held for later alphas
• Faster startup
• Wider hardware testing

Licence and credits

Apache License 2.0. Keep the NOTICE file with any copy, and credit mcopt. Files adapted from Sodium keep the PolyForm Shield License 1.0.0. Each of those files says so in its header, and NOTICE lists them. mcopt runs on top of Sodium, by JellySquid and its contributors.