Project Zomboid is a great example of a game built on a dinosaur-era engine that has somehow survived to this day. Unfortunately, the default amount of RAM allocated to Project Zomboid is barely enough if you don’t plan to play a purely vanilla game.

However, if you intend to play a heavily modded Zomboid in singleplayer or, for example, on a heavily modded hardcore PvP server like Campfire, you may notice frequent micro-freezes — this is largely due to the limited RAM allocated to Project Zomboid.

To allocate additional RAM, follow these simple steps:

1. Navigate to: Steam\steamapps\common\ProjectZomboid;
2. Find ProjectZomboid64.json and open it with Notepad;
3. Locate the section called "vmArgs";
4. Right under the parameter "-Djava.awt.headless=true", add the following parameters: "-Xms6g" and "-Xmx16g", where Xms is the minimum amount of RAM allocated to Project Zomboid, and Xmx is the maximum;
5. Save the changes and enjoy a (mostly) freeze-free gameplay experience.

In the end, it should look something like this:

Note: You are free to insert your own values for minimum and maximum RAM depending on your needs. On our Ukrainian server Campfire, aimed at players from across Europe, we recommend using "-Xms6g" and "-Xmx16g".

Thank you for your attention!