FluidCore

FluidCore is a lightweight Fabric performance mod that optimizes Minecraft's vanilla fluid tick system for both singleplayer and multiplayer servers.

How It Works

Vanilla Minecraft ticks every single water and lava block every few game ticks — even blocks that haven't changed in minutes, and even when no player is nearby. FluidCore introduces a smart sleep/wake system that eliminates this wasted CPU time.

Distance-based sleeping — Fluid blocks farther than 96 blocks from any player are put to sleep and stop ticking
Stability counter — Fluid blocks that haven't changed for 60 ticks are gradually put to sleep, even near players
Event-driven wake-up — Sleeping fluids instantly wake up when a nearby block changes, ensuring correct behavior
Chunk unload cleanup — Sleeping fluid data is automatically cleaned when chunks unload, preventing memory leaks
Both source and flowing blocks — Optimizes both water/ lava source blocks and flowing blocks

Benchmarks

Tested with Spark profiler on Fabric 1.20.1:

Metric	Vanilla	FluidCore	Improvement
Fluid tick CPU usage	2.63%	2.29%	~13% reduction

Tested on a flat world with a large water area. Results may vary depending on world complexity.

Compatibility

✅ Fabric 1.20.1
✅ Works in singleplayer
✅ Compatible with vanilla clients (server-side only)
✅ Compatible with Sodium, Lithium, and other performance mods

Installation

Install Fabric Loader
Install Fabric API
Drop FluidCore into your mods folder
Launch the game

Enjoy!