What Chlorine does

Small adjustments. A more considered world.

Chlorine is a Fabric performance and power-management mod for Minecraft 26.3. It targets CPU-side simulation work, bursty entity effects, and laptop power usage while leaving chunk rendering and renderer internals to specialized mods.

Adapt to the moment

Adaptive client tuning

Adaptive simulation distanceMonitors a rolling FPS average and lowers simulation distance when performance falls below the configured threshold, then raises it again after a recovery cooldown.

Entity-distance scalingCan reduce the entity-distance multiplier after simulation distance reaches its configured floor.

Particle fallbackCan reduce the particle setting as a last resort.

Simulation-distance capOptionally prevents other tuning systems from raising simulation distance above a fixed ceiling.

Fast-travel chunk governorTemporarily lowers simulation distance while moving quickly (Elytra, Riptide trident), then restores it after a cooldown.

Chlorine intentionally changes simulation distance, not render distance. Render-distance changes can rebuild the entire chunk render graph and cause a large hitch; simulation distance instead targets server ticking, entity updates, random ticks, and block updates.

Ease background work

Server and gameplay-side optimization

Distant classic-mob AI throttleStaggers goal-selector AI for mobs such as zombies and skeletons when no player is nearby. Physics and nearby mobs are not throttled.

Distant Brain-mob throttleApplies the same idea directly to Brain.tick() for villagers, piglins, hoglins, allays, frogs, and other Brain-driven mobs.

Item mergingPeriodically combines compatible nearby item entities around online players.

XP orb mergingCombines nearby experience orbs. Verifies the internal value update before discarding an orb and disables itself for the session if that operation cannot be verified.

Server tick diagnosticsOptionally logs a warning when average server tick time exceeds the configured threshold. Observability only; it does not alter server behavior.

Make busy moments gentler

Client effects and power saving

Unfocused-window power saverCaps FPS while the game window is unfocused or minimized and can hide clouds during that period.

Sound budgetLimits how many new sounds may start in one client tick, smoothing bursts from farms, combat, or other events.

Sound pre-cullDrops very quiet distance-attenuated sounds before they reach the audio engine.

Particle budgetLimits particle creation per client tick to smooth fireworks, explosions, potion clouds, and similar bursts.

Beacon and portal throttlesSkips distant beacon beams and Nether portal ambient particles when enabled.

Low-end auto-tuneOnce per launch, detects constrained memory or CPU availability and applies lighter vanilla visual defaults.

Protect the 1% lows NEW IN 1.0.6

Frame smoothing and render LOD

Light update smoothingWhen a large backlog of light updates builds up, processes it within a per-frame time budget instead of all at once, with a minimum amount of progress each frame.

Adaptive ambient effectsScales down ambient block effects such as dripping and smoke while the frame rate is under pressure, and restores them once it recovers.

Sign text LODSkips drawing sign text beyond a configurable distance, where it is too small to read anyway.

Item drop LODDraws distant dropped stacks as a single item instead of a pile of copies.

Block entity LODSkips small, distant block entities such as chests and skulls. Large or always-visible ones, like beacon beams, are left alone.

Autosave smoothingThe periodic autosave writes a limited number of chunks immediately and hands the rest to the game's own background saver, so nothing is lost and the 5-minute hitch shrinks.

Work with the renderer

Sodium-aware workload control

Builder-pressure governorSamples Sodium's existing chunk-builder queue and worker occupancy at the verified render-list boundary.

Frame-pacing protectionDefers immediate terrain updates only when sustained low FPS, a real queued-job backlog, and a stable camera agree that synchronous work is contributing to pressure.

Hysteresis and recoveryAvoids rapid toggling and restores normal behavior after the frame rate recovers or pressure clears.

Adaptive chunk upload budget NEW IN 1.0.7Lowers Sodium's 10 ms minimum per-frame chunk upload time so uploads can't outlast a frame at high FPS. The full budget is kept for the first seconds after joining so terrain still fills in quickly.

Nearby rebuild scaling NEW IN 1.0.7While FPS is low, shrinks the radius in which block changes are rebuilt and shown immediately on the main thread, which softens hitches from TNT, pistons and redstone.

Async culling under pressure NEW IN 1.0.7While FPS is low, keeps Sodium's visibility culling on its background thread during fast camera movement, instead of switching to the main thread.

Sodium GPU profileCan enable Sodium's exposed fog occlusion, block-face culling, and visible-texture animation settings without replacing Sodium's OpenGL renderer.

The three 1.0.7 additions patch Sodium's internals rather than its public API. If a future Sodium version changes that code, they switch themselves off instead of crashing the game.

This integration is designed for Chlorine 1.0.3+ on Minecraft 26.3 and requires Sodium 0.9.2 or newer. It does not add entity culling, replace Sodium's worker pool, or claim an unverified GPU speedup.

Keep the heap healthy NEW IN 1.0.8

Memory governor

Cache trimmingEmpties Chlorine's own collision cache when heap usage passes a configurable percentage, 85% by default.

GC after leaving a worldRequests one garbage collection on a background thread after you leave a world, at most once a minute, so the menu never freezes. Ignored if the JVM runs with -XX:+DisableExplicitGC.

Leak watchLogs a warning if memory kept after garbage collections keeps growing. It only logs and never changes behavior.

Java's garbage collector is chosen by your launcher's JVM flags, so a mod cannot replace it. For the biggest memory-related gains, use G1 or Generational ZGC with 6 to 8 GB allocated.

Choose what stays on

Your configuration

All features are independently configurable and can be disabled without removing the mod. Configure them in-game with Cloth Config, optionally surfaced through Mod Menu, or edit config/chlorine.json directly.

Simulation Distance CapAdaptive ScalerPower SaverMob AI ThrottleItem MergingXP Orb MergingSound BudgetParticle BudgetLow-End Auto-TuneBeacon & Portal ThrottleChunk Gen GovernorSound Pre-CullFrame SmoothingRender LODSodium Workload GovernorsSodium GPU ProfileTick DiagnosticsMemory Governor The in-game config screen groups settings into these categories · highlighted ones are new or expanded in 1.0.6, 1.0.7 and 1.0.8

Chlorine 1.0.3+ requires Sodium for its direct renderer integration. Lithium, FerriteCore, EntityCulling, ImmediatelyFast, Iris, and Mod Menu remain optional companions.

A note on performance

Results depend on your world.

Entity count, hardware, and other installed mods all matter. Defaults are conservative, not universal benchmarks. Sodium's workload governor is intended to protect frame pacing under chunk-build pressure, not guarantee a universal FPS increase. The demos on this page are illustrations of each idea, not measurements.