Project Zomboid: How to Allocate More RAM
Project Zomboid is an incredibly memory-intensive game, especially when you start adding high-fidelity mod packs like Brita's Weapon Pack or large map expansions. By default, the game only requests a small portion of your system's memory. If you experience "stuttering," "map holes," or crashes while loading, you likely need to **Increase your RAM Allocation.**
1. The 2GB Limit
By default, Project Zomboid often starts with just 2GB or 3GB of RAM. In a modern modded environment, this will cause the Java Virtual Machine (JVM) to run out of memory and crash the game.
2. Mod Bloat
Every item, vehicle, and tile introduced by a mod is loaded into your RAM. If your game takes more than 5 minutes to load into the main menu, you definitely need to allocate more memory.
3. Build 42 & Multiplayer
The new Build 42 architecture is far more demanding. For any multiplayer server on the Unstable branch, **8GB - 9GB of RAM is the new MINIMUM** to prevent constant desync and crashes.
How to Manually Increase RAM (Steam Version)
- Open your Steam Library.
- Right-click Project Zomboid and select Manage > Browse Local Files.
- Locate the file named
ProjectZomboid64.json. - Right-click the file and select Edit (with Notepad or Notepad++).
- Look for the line containing
-Xmx. It will likely look like this:"-Xmx3072m", - Change the number to match your desired RAM size in Megabytes (MB).
- 4GB:
-Xmx4096m - 6GB:
-Xmx6144m - 8GB:
-Xmx8192m
- 4GB:
- Save the file and launch the game.
Recommended Memory Settings
| Playstyle | Recommended RAM | Notes |
|---|---|---|
| Vanilla (Singleplayer) | 4GB | Smooth experience with zero stuttering. |
| Modded (10-50 Mods) | 6GB | Necessary for basic weapon and vehicle packs. |
| Heavily Modded (100+ Mods) | 8GB - 12GB | Required for high-particle effects and global map overhauls. |
| Local Host (Hosting Friends) | 8GB+ | You are running both the client and the server; memory usage is doubled. |
Warning: Never allocate more than 50% of your total system RAM. If your computer has 16GB of RAM, do not set the game to 16GB, or your Operating System (Windows/Linux) will not have enough memory to function, causing a Blue Screen or system freeze.
Zero stutter, max survival. Host your Project Zomboid server with Supercraft and let our dedicated infrastructure handle the heavy memory lifting, while your local PC stays fast and responsive.