# Arma 3 server performance and requirements

> How much RAM and CPU an Arma 3 server needs, what server FPS means, why AI counts matter most, and how to keep big operations smooth.

By the Wilderack Crew. Last reviewed 2026-11-13. Topic: Performance tips.

_Wilderack is not affiliated with Bohemia Interactive. Arma 3's server license is for personal use, so Arma 3 servers open on Wilderack only once Bohemia gives us its written OK._

_Arma 3 is a trademark of Bohemia Interactive a.s. Wilderack is not affiliated with or endorsed by Bohemia Interactive a.s._

An Arma 3 server spends most of its time on AI: every soldier, vehicle and patrol a mission spawns. That work runs on one main thread, so a fast core matters more than more memory or more cores. This guide covers the RAM to plan for, how to read server FPS, and what to change when a big operation gets slow.

> [!NOTE]
> Arma 3 servers can't be ordered on Wilderack yet. We open Arma 3 once Bohemia Interactive gives us its OK. Before then we'll measure big modded missions on our own machines and size the plans from what we see.

## How much RAM to plan for

| Your server | RAM |
|---|---|
| A small group, up to about 20 players | 4 GB |
| Most missions, up to about 40 players | 6 GB |
| ACE, RHS, CUP or other big mod sets | 8 GB |
| Big modded operations, up to 100 players | 12 GB |

Our [RAM calculator](https://wilderack.com/tools/game-server-ram-calculator/) gives the same advice for your player count and mods.

## Server FPS

The server updates the mission many times a second, up to 50. That rate is its FPS, and it's the best sign of health. Check it in game: log in as admin and type `#monitor 5`.

| Server FPS | What players notice |
|---|---|
| 40 to 50 | Smooth |
| 20 to 40 | Fine for most missions |
| Under 20 | AI react late, vehicles jump, hits land late |
| Under 10 | Desync: players and AI rubber-band |

## What costs the most

1. **Active AI.** The biggest cost by far. A mission with 300 AI awake works the server much harder than one with 60.
2. **Scripts.** Missions and mods that run a lot of code each frame.
3. **Players spread across the map**, since each one keeps AI and objects near them awake.
4. **Mods** add memory more than CPU, unless they add scripts.

## Keep a big operation smooth

- **Cap the AI.** Most missions let you set how many AI spawn. Lower it before anything else.
- **Turn on Dynamic Simulation** in the mission. It sleeps AI and objects far from players, so they cost nothing until someone comes near.
- **Clean up.** Wrecks and bodies pile up over a long session. Most missions have a garbage collector; turn it on.
- **Restart between sessions.** A scheduled restart in **Schedules** clears out memory that builds up.
- **Pick the region closest to your players.** US East and Europe are open now.

## Headless clients

A headless client is a second copy of Arma 3 that takes AI off the server's main thread. Big communities use one for AI-heavy missions. We'll check whether one can run beside the server on Wilderack before Arma 3 opens.

## Tuning basic.cfg

`basic.cfg` sets how much data the server sends each frame. The defaults are fine for most groups. If many players on good connections see desync while server FPS is high, raising `MaxMsgSend` and `MinBandwidth` a little can help. Change one value at a time. The [config reference](https://wilderack.com/wiki/arma-3/config-reference/#basiccfg) explains the file.

## Read the graphs

The **Overview** tab shows CPU and memory over time. If memory sits near the top of your plan, move up a plan or drop a big mod. If CPU is high and server FPS low, cut the AI.

## Questions and answers

### How much RAM does an Arma 3 server need?

At least 4 GB. Most missions with up to 40 players run well on 6 GB, and big mod sets like ACE, RHS and CUP need 8 GB or more, since the server loads their data into memory.

### How do I check my Arma 3 server's FPS?

Log in as admin and type

### Why does my Arma 3 server lag with lots of AI?

The server runs AI on its main thread, so every soldier and vehicle the mission spawns costs server time. When there's too much, server FPS drops and players see AI and vehicles stutter or jump. Fewer active AI is the biggest fix.

## Sources

- [Arma 3: Dedicated Server](https://community.bistudio.com/wiki/Arma_3:_Dedicated_Server), Bohemia Interactive Community Wiki
- [Arma 3: Basic Server Config File](https://community.bistudio.com/wiki/Arma_3:_Basic_Server_Config_File), Bohemia Interactive Community Wiki
- [Arma 3: Headless Client](https://community.bistudio.com/wiki/Arma_3:_Headless_Client), Bohemia Interactive Community Wiki
- [Multiplayer Server Commands](https://community.bistudio.com/wiki/Multiplayer_Server_Commands), Bohemia Interactive Community Wiki

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