Memory Leak Fix — a mod for fixing memory leaks in Minecraft

Memory Leak Fix — a mod for fixing memory leaks in Minecraft

Memory Leak Fix is a mod for Minecraft that fixes several memory leaks in the game itself. A leak is a situation where memory that the game should have already freed remains occupied and keeps building up over the course of a session. Because of this, RAM usage gradually grows during long play sessions, freezes appear, and on weaker setups it can even lead to a crash. The mod works on both the client and the server, doesn't change gameplay, and requires no configuration at all — it simply fixes problem areas in how the engine works. 

Which memory leaks the mod fixes

In build v1.1.4, the mod contains seven separate leak fixes. Most of them relate to older issues that Mojang later fixed in the game itself, so only two remain genuinely useful on later versions.

The first and most noticeable fix concerns the biome temperature cache. This cache took up a large amount of memory while also working incorrectly. The mod fixes its behavior, so operations related to biome temperature run faster and consume noticeably less memory. The second fix eliminates a leak that occurs when returning to the main menu: the game wasn't releasing certain references, so the previous world effectively stayed loaded in memory even after you left it. The mod correctly releases this data, so memory is actually freed once you return to the menu.

The remaining fixes cover historical engine bugs — for example, memory that wasn't cleared from entity "brains" after death, unreleased custom tags when there are large numbers of recipes and loot tables, and leaks related to working with textures and saving large screenshots. These issues mostly affect older versions and were closed by updates to the game itself on newer ones.

Client and server performance

The mod is universal in terms of where it can be applied. Some fixes work simultaneously on both the client and server side, while others apply only to the client. This means it's beneficial both in single-player and on a dedicated server, where memory usage is especially noticeable due to the large amount of loaded content and long uptime. Installing it on a server works the same way as installing any other mod for your chosen loader.

Summary

Memory Leak Fix is a small technical mod that doesn't add new content or change any visuals — it just removes several sources of excessive memory consumption. It has no configuration, doesn't conflict with gameplay, and is equally suitable for client and server. For older versions of the game where the corresponding leaks haven't been officially fixed, installing it helps make long play sessions more stable and a bit lighter on RAM.