Project Zomboid Ultimate Performance Guide

Hello! This guide is designed to help with performance in our modded Project Zomboid server. We have a large number of mods installed that add lots of maps, vehicles, and other assets; requiring a more powerful machine than the developers originally envisioned.

For this reason, we advise that you ensure your system at least meets the recommended specs listed below.

While this guide can help improve framerates and your experience in-game, we cannot add hardware to your machine. If your system does not meet or exceed the specs below it may even refuse to boot.

1. Find your Zomboid install location. By default it's C:\Program Files (x86)\Steam\steampps\common\ProjectZomboid
2. Locate a file titled ProjectZomboid64.json and edit it in your Notepad application
3. In that file, look for the following entry (you may only have Xmx3072m):
   • -Xms3072m,
   • -Xmx3072m,
4. Edit these lines to give yourself the appropriate amount of RAM. 1 GB is 1024 MB. Here's a quick list of values below:
   • 4 GB —→ Xmx4096m,
   • 6 GB —→ Xmx6144m,
   • 8 GB —→ Xmx8192m,
   • 12 GB —→ Xmx12288m,
5. Save the file and run the game normally.

Occasionally you may be asked to “verify files”, or verify the integrity of your game files. This is due to either the files becoming corrupted or mismatched. In that case, follow the guide linked below:

• Steam Support :: Verify Integrity of Game Files