Iridium
by startred_
With Iridium installed, the game skips drawing entities, particles and block entities that sit outside the camera view, which targets stutter in busy scenes.
What it does
Iridium adds rendering optimizations for Minecraft 1.21.1 that work alongside Sodium and Lithium by covering rendering work they leave alone. Its culling features skip entities outside the camera frustum, cull particles and cap active particle counts, and skip chests, furnaces, beacons and shulkers that are off-screen. Map textures are re-uploaded only when the map data has changed.
On the server side, Iridium throttles hoppers, explosions, villager AI and projectiles, and it can lower the frame rate while the game window is unfocused. It is built as a companion to Sodium Lithium and can replace it. When another mod overlaps a feature, Iridium detects the conflict and disables its own hook so the same work is not done twice. It works on a client, a dedicated server or both, and a feature that does not apply to the current environment does nothing. Files are published for Minecraft 1.21.1 only, and the license is custom and not open source.
Key features
Entity and particle culling
Entities and particles outside the camera frustum are skipped, and particle counts are capped with fireworks tracked separately.
Block entity culling
Chests, furnaces, beacons and shulkers outside the view are not drawn, and beacon beams are culled the same way.
Nametag and map caching
Nametag text is cached between frames and map textures are re-uploaded only after the map data changes.
Server-side throttling
Hoppers, explosions and villager AI are throttled on the server, and throttles only activate near players.
Gallery
Compatibility
Latest build for each game version and loader.
Only full game releases are shown. This mod publishes no snapshot builds.
How it compares
Culler is a client-side only Fabric mod that is open source under the MIT License and covers Minecraft 1.21.1 – 1.21.10, so it reaches later versions than Iridium. Sodium Leaf Culling is open source under the MIT License, runs client-side only and is published for Fabric and NeoForge on 1.21.1, which makes it an option for NeoForge players.
| Mod | Loaders | Game versions | Environment | Updated |
|---|---|---|---|---|
| Iridium | Fabric | 1.21.1 | Client or server, optional | 2026-04-22 |
| Culler | Fabric | 1.21.1 – 1.21.10 | Client-side only | 2025-11-23 |
| Sodium Leaf Culling | Fabric and NeoForge | 1.21.1 | Client-side only | 2025-04-07 |
Questions
Does Iridium need to be installed on the server?
Which Minecraft version does Iridium support?
Does Iridium work alongside Sodium and Lithium?
In the catalog
Iridium is one of 3,545 Optimization mods on ModsFinder, and one of 2,575 Optimization mods for Fabric. 32,366 mods support Minecraft 1.21.1.
Similar mods
What the author says
Iridium is a modern Fabric optimization mod for Minecraft 1.21.1, designed to complement Sodium and Lithium by covering optimizations they do not include — entity and particle culling, block-entity culling, server-side throttles for hoppers, explosions, villager AI, projectiles, and dynamic FPS when the game window…
Official listing
- Modrinth page
- modrinth.com/mod/iridiummod
- Owner
- startred_
- Published
- 2026-04-19
- Updated on Modrinth
- 2026-04-22
- Facts verified
- 2026-10-15