ImmediatelyFast vs Immersive Optimization

ImmediatelyFast is a free, open source Minecraft mod that improves client-side rendering performance in Minecraft: Java Edition. It batches draw calls using a custom buffer and sends data to the GPU more efficiently. Its optimizations cover entities, block entities, particles, text, GUI and HUD, maps, and immediate mode rendering used by other mods. The project supports Fabric, Forge, NeoForge, and Quilt, with compatibility listed for Minecraft versions 1.18.2 through 1.21.x and versions 26.1.x, 26.2, and 26.3. It is designed to work with most mods and modpacks, but names OptiFabric, OptiFine, LunarClient, and LabyMod as incompatibilities. The project says it can improve FPS when the CPU is the bottleneck, with slower CPUs benefiting more than very fast ones. A configuration file in the Minecraft instance’s config folder offers performance or compatibility options. The mod is licensed under LGPL-3.0-or-later, and developers can consult API documentation. The project links to a GitHub issue tracker and Discord server for support.

Immersive Optimization has no write-up on Specifiction yet; its figures are above.