Project Zomboid Server Lag: How to Fix Rubberbanding

To fix Project Zomboid server lag, first sort it: if every player rubberbands, the server is overloaded, and if only one player does, it is that player's connection. For the server, update to the latest build, remove the newest mods, lower zombie population, check memory and make sure the server is close to your players.

Is it server lag or player lag?

"The server is lagging" can mean four different problems. Sort them out before you change anything:

Step 1: update to the latest build

Many lag problems have been fixed in updates. The Indie Stone's patch notes show it:

• 42.20.3 "addressed multiple causes of a memory leak that could lead to performance degradation and crashes over time".
• 42.21 fixed zombies disappearing after a player leaves and re-enters a chunk, and multiplayer zombie duplication, which were "particularly obvious in larger zombie population games". It also fixed problems when driving with high ping, about 150 and up.
• 42.22 Pre-Release improved the performance of server backup creation.

Run the latest Stable build on the server and make sure every player does too. Build 42 vs Build 41 explains the branches. A client and a server on different builds cause more than lag, so check that first if players are being refused.

Step 2: remove your newest mods

Mods are the most common reason a server that worked yesterday is slow today. Map mods and big content mods cost the most. To test:

1. Make a backup. In our panel, open Backups and create one.
2. Remove the last mod you added from the WorkshopItems= and Mods= lines in the server .ini file.
3. Restart and compare. Watch the server with players on.
4. Add mods back one at a time.

How to add mods to a Project Zomboid server covers the two IDs every mod has.

Step 3: lower the zombie load

Every zombie is something the server has to track. High population, a high peak and fast respawn put more load on the server, especially with many players. In servertest_SandboxVars.lua, look at Zombies, the ZombieConfig multipliers and ZombieRespawn. Lower one value, restart and test. Project Zomboid sandbox settings lists the key names.

Step 4: check memory

A server that runs out of Java memory shows long freezes, crashes and out-of-memory messages in the console, not just lag. The Indie Stone's patch notes tell players who keep seeing an out-of-memory error in a new save to send a bug report with their logs, so check the console first.

Look at the memory figure at the top of your server page in the panel. If it sits close to your plan's limit, the server needs more room. PZwiki's rule of thumb is at least 3 GB plus about 500 MB for each additional player, and more for mods. Project Zomboid server requirements explains how to size a plan. More RAM only helps if memory is the problem, so confirm it first.

Step 5: look at your player load

Each player keeps their own area of the world loaded. Players who spread across the map cost more than players who stay together. If lag grows as more people join:

• Lower MaxPlayers in servertest.ini.
• Use PingLimit to kick players whose ping is far above the rest.
• Ask your group to base in the same area, or to avoid long drives with a car at the same time.

Step 6: choose the right location

Ping decides how rubberbanding feels. Put the server near most of your players: Dallas, TX for the Americas or Amsterdam, NL for Europe. A player far from the server will always feel more lag than the others. Our Location Changer moves the server between the United States and Europe.

Step 7: save and backup timing

The server saves the world every SaveWorldEveryMinutes minutes, and backups also take work. If lag comes in regular pulses, compare the timing with your save interval and with any backup schedule. Move scheduled backups to the quietest hours.

Is it a network attack?

If everyone's ping jumps at once and recovers, the cause may be network traffic. Every TheGameHosting server sits behind DDoS protection that filters attack traffic. You can also check our status page.

A quick lag checklist

1. Is the server on the latest Stable build, and are the players too?
2. Did the lag start after a new mod, an update or a settings change?
3. Is memory close to the plan's limit?
4. Do all players lag, or only one?
5. Is the server in the same region as most of your players?
6. Did you change the zombie settings recently?

What not to do

• Do not set -Xmx above your physical RAM. PZwiki says that pushes the server into virtual memory, which slows it down.
• Do not turn off DoLuaChecksum to hide a problem. It only silences the error and leaves modified files on the server.
• Do not add five mods at once to fix one problem.

What to send our support team

If the lag is still there, our support team answers 24/7 through live chat, email and tickets. A good report gets a faster answer:

1. Your build number from the game's main menu.
2. Your mod list: the WorkshopItems= and Mods= lines.
3. How many players are online when the lag starts, and where they are in the world.
4. When it began. Was it after an update, a new mod or a settings change?
5. The last lines of the console if you see errors.

FAQ

Hosting for this game

• Project Zomboid server hostingSteam Workshop mods, sandbox settings and no slot fees