7 min read Beginner Updated: Agrar Chaoten Team

Short answer

Why is my FS25 server slow even though only 2 players are online?

Player count is often not the cause. Most common reasons: too many AI vehicles (AutoDrive, Courseplay), faulty mods, a weak server CPU or an oversized savegame.

Players are often not the problem

Many FS25 players assume: fewer players = faster server. That's only partly true. FS25 servers can lag heavily even with just 1–2 players — when the real cause lies elsewhere.

Important note: FS25 is largely single-threaded. That means the entire game logic runs on a single CPU core. Whether 2 or 16 players — the CPU load per tick stays similar, because mods, AI and physics do the same work.

Cause 1: Too many active AI vehicles

This is by far the most common cause of lag with few players. Every AI-controlled vehicle (AutoDrive, Courseplay, workers) constantly calculates routes, collisions and actions on the server core.

  • 10 AI vehicles running at once can completely max out a weak CPU
  • Fix: Reduce AI vehicles, don't run them all at the same time

Cause 2: Weak server CPU

If your server runs on older hardware with weak single-core performance, that's often the root of the problem. Classic server processors are often built for multi-core enterprise workloads — not for single-core gaming.

Cause 3: Autosave and saving too often

Every time the server saves, there's a brief spike in load. That's normal and usually only lasts 1–2 seconds. It becomes a problem when:

  • The savegame is very large (lots of vehicles, lots of objects in the inventory)
  • Several players save manually at the same time ("Saving while already saving")
  • The autosave interval is set too short

Fix: Increase the autosave interval to 15–20 minutes, sell unneeded vehicles to shrink the savegame.

Cause 4: Faulty or incompatible mods

Some mods have script errors that cause constant CPU overhead. You can spot this in the server log by recurring ERROR entries.

1

Open the server log

In the web interface under "Logs" or directly in the server's log.txt file.

2

Search for "Error"

Recurring LUA errors point to a problematic mod. The mod name is usually part of the error text.

3

Disable the problematic mod

Disable one mod after another until the error disappears.

Cause 5: Map with too many trees or objects

Some map mods exceed the FS25 tree limit (30,000). We've seen this in an actual server log: "NumTrees: 32.554 / MaxNumTrees: 30.000" — that's 2,554 trees over the maximum. That alone can cost performance.

Quick checklist: what to check?

  • ☐ How many AI vehicles are running at the same time right now?
  • ☐ Check the server log for ERROR entries
  • ☐ Check the savegame size (sell vehicles)
  • ☐ Check the autosave interval (15–20 min is ideal)
  • ☐ Which CPU does your server provider use?
  • ☐ Install SimpleInspector and watch the TPS live

Frequently asked questions

Why is my FS25 server slow even though only 2 players are online?
Player count is often not the cause. Most common reasons: too many AI vehicles (AutoDrive, Courseplay), faulty mods, a weak server CPU or an oversized savegame.
Can the server CPU be responsible for FS25 lag?
Yes — and it's an often overlooked reason. FS25 runs single-threaded. What matters is the single-core performance of the server CPU, not the number of cores.
How do I measure my FS25 server's TPS?
Install the SimpleInspector mod (shows the TPS live in-game) or install AutoDrive (automatically writes the TPS to the log.txt file).

Questions about this guide?

Stuck on a step? Get in touch – we're happy to help.

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Last updated: 2026-05-17 · Written by the Agrar Chaoten team