Buffer
Buffer is a Fabric optimization mod for the client that clears stale memory during long play sessions, so frame pacing stays steady after hours in the game.
What it does
Buffer targets gradual slowdown that builds up when Minecraft stays open for many hours. Over time, unused texture and model data, leftover vertex buffers and tracking records for unloaded entities can pile up, and the game may begin to stutter. The mod runs a set of cleanup passes in the background to release that memory, aiming at stability over a long session rather than a higher frame rate.
Buffer is a client-side only mod, so only the player's game needs it and servers run without it. It is published for Fabric alone, across 11 game versions 1.21.1 – 1.21.11, and its latest file is 1.1.0 for 1.21.11. The code is under the MIT License, so the project is open source. Public source code, an issue tracker and a wiki are available.
The mod is installed like any other Fabric mod, with Fabric Loader and its usual setup. It works with the default settings, and the author recommends the ZGC garbage collector in launcher settings for strong results. Buffer is also listed as compatible with Sodium, Lithium and Iris.
Key features
Background texture cleanup
Old textures and model data that are no longer in use are removed in the background, without pausing play.
Vertex buffer release
Vertex buffers no longer needed are explicitly freed from system and GPU memory as the player moves between chunks.
Dimension change sweep
A deeper memory pass runs each time the player switches dimensions, such as when entering the Nether.
Ghost entity cleanup
Tracking data for entities that have already unloaded is found and removed, which frees CPU time right away.
Gallery
Compatibility
Latest build for each game version and loader.
1.21.x11 of 11 versions with builds
Only full game releases are shown. This mod publishes no snapshot builds.
Use cases
Who it’s for: Players who keep Minecraft open for long stretches and notice stutters that build up over the session, rather than right at launch.
How it compares
ChatLagFix is a Fabric client mod for 1.21.11, open source under the MIT License, and it targets chat-related lag rather than memory. MChat Fix is a Fabric client mod for 1.21.11 with all rights reserved, so its code is not open source. Session Stats is a Fabric client mod for 1.21.11 under the MIT License, but it is not open source and reports session figures instead of cleaning memory.
| Mod | Loaders | Game versions | Environment | Updated |
|---|---|---|---|---|
| Buffer | Fabric | 1.21.1 – 1.21.11 | Client-side only | 2026-04-01 |
| ChatLagFix | Fabric | 1.21.11 | Client-side only | 2026-03-17 |
| MChat Fix | Fabric | 1.21.11 | Client-side only | 2026-06-10 |
| Session Stats | Fabric | 1.21.11 | Client-side only | 2026-03-09 |
Questions
Does Buffer need Fabric API?
Does Buffer have to be installed on the server?
Which game versions does Buffer support?
In the catalog
Buffer is one of 3,545 Optimization mods on ModsFinder, and one of 2,575 Optimization mods for Fabric. 19,862 mods support Minecraft 1.21.11.
More from Maldeq-crypto
Similar mods
What the author says
🕒 LongerPlaying The "Zero-Reset" Performance Utility. LongerPlaying is a lightweight, engine-level optimization mod for Fabric 1.21.1 – 1.21.11. It is specifically designed to solve "Session Decay"—the gradual accumulation of lag and stuttering that occurs when Minecraft is left running for several hours.
Official listing
- Modrinth page
- modrinth.com/mod/longerplaying
- Owner
- Maldeq-crypto
- Published
- 2026-03-12
- Updated on Modrinth
- 2026-04-01
- Facts verified
- 2026-10-15