How Many CPU Cores and How Much RAM Does an Arma Reforger Server Need?

Most sizing advice for game servers is a table of player counts against gigabytes. For Arma Reforger that table is misleading, because player count is one of the weaker predictors of how hard the server is working.

What actually limits a Reforger server is the simulation tick, and what limits the tick is single-thread CPU speed and the number of entities it has to advance. That reframes the question from "how many players" to "how much simulation".

What actually constrains the server#

Single-thread CPU speed. The Enfusion simulation tick is largely serial. A fast core running the tick quickly gets you a higher server frame rate than several slow cores, at the same price. This is why hosts that care about Reforger specify high-clock parts rather than the highest core counts they can buy.

Thread count, up to a point. Reforger does make use of multiple threads, but in practice not more than about six. Past that, additional threads sit largely idle.

AI count. Every AI unit is simulated server-side: pathing, perception, ballistics. This is the dominant variable on Conflict servers and the reason two servers with the same player count can perform completely differently.

View distance. serverMaxViewDistance and networkViewDistance determine how much the server has to simulate and stream per player. Raising them multiplies work.

RAM, as a floor. Memory is a threshold rather than a dial. Enough and it is a non-issue; not enough and the server fails or thrashes. Large modlists and terrain mods raise the floor.

Starting points by community size#

These are the presets we size Arma Reforger servers around, and they are reasonable starting points wherever you host:

Adjust up from these if you run a heavy modlist, uncapped AI, or view distances well above default. Adjust down if you run Capture & Hold or another PvP mode with AI disabled — those are dramatically cheaper to run than Conflict at the same player count.

Storage is mostly about mods. The base game needs little; a modlist with multiple terrains can need tens of gigabytes on its own.

Why the same slot count can need very different hardware#

Two 48-player servers:

• Conflict on Everon, AI uncapped, view distance 2500. Hundreds of AI, wide streaming radius, persistent campaign state. This is the expensive configuration.
• Capture & Hold, disableAI: true, view distance 1600. No AI simulation at all, tight streaming, short rounds. Comfortable on a fraction of the resources.

Same slots, very different load. If you are trying to work out what you need, the scenario and the AI settings tell you more than the player cap does.

What to do before buying more#

If a server is struggling, tuning usually beats upgrading — and it is free:

1. Cap AI. operating.aiLimit defaults to -1, meaning unlimited. Setting a cap is the single highest-impact change available.
2. Bring view distance back toward default. 1600 for serverMaxViewDistance, 1500 for networkViewDistance.
3. Check the modlist. Individual mods can be disproportionately expensive, particularly ones that add AI behaviour or dense props.
4. Read the frame-time graph, not the player count. Server FPS against entity count over time tells you which of these is actually your problem.

Performance tuning covers each of these with the specific fields and sensible values.

Verify you sized it right#

1. Run a genuinely full session — sizing conclusions from an empty server are worthless.
2. Watch server FPS through the busiest part of it. Sustained drops during firefights, not the average, are what players feel.
3. Correlate the drops with entity count. If FPS falls as AI climbs, cap AI before buying cores.
4. Check memory headroom at peak. Near the ceiling means raise RAM; comfortable means RAM is not your problem, whatever else is.
5. Re-check after every significant modlist change.

Trusted references#

• Arma Reforger: Server Hosting — Bohemia Interactive's official hosting documentation
• Arma Reforger: Server Config
• Arma Reforger: Startup Parameters