How it works

Garbage Collector pressure reduction. Minecraft creates and discards thousands of temporary objects every second — arrays, lists, string builders. Every discarded object adds work for Java's Garbage Collector, which causes micro-stutters when it kicks in. Thulium pre-allocates reusable object pools and borrows from them instead of creating new objects. It also monitors memory usage and prevents unnecessary GC cycles that vanilla triggers too often.

Sound engine optimization. The sound system is surprisingly expensive. In areas with many sound sources, OpenAL processing becomes a real CPU bottleneck. Thulium caps simultaneous sounds per category, removes duplicate sounds playing at the same location within 50ms, and culls sounds beyond effective hearing range based on their volume. A global limit of 80 simultaneous sounds prevents overload while prioritizing important audio like music and voice.

Forge Event Bus optimization. The event bus fires hundreds of events every tick. Many of them have zero listeners — no mod is actually waiting for them, but the bus still processes them anyway. Thulium periodically scans the bus, identifies events nobody is listening to, and marks them as skippable.

Profiler overhead removal. Minecraft runs its built-in profiler at all times, even when the F3 debug screen is closed. Every frame, thousands of push/pop/swap calls execute just to track performance sections that nobody is looking at. Thulium replaces the active profiler with a no-op version when F3 is closed, removing all that overhead. When you open F3, it restores automatically.

Render loop optimization. Minecraft leaves several unnecessary OpenGL features enabled — dithering, line smoothing, point smoothing. Thulium disables them and sets GPU driver hints to prefer speed over quality for internal calculations. It also monitors your FPS in real-time and adapts its aggressiveness — switching to a more aggressive mode when performance drops.

Expected results

Overall FPS improvement is roughly 15-25% depending on your system. On CPU-bound setups the difference is more noticeable. The mod also significantly reduces micro-stutters caused by garbage collection.

Does not modify entities, blocks, chunks, lighting or world generation.