Subnautica 2 Co-Op Server Provisioning via AMP

Subnautica 2 ships with the first officially supported dedicated server in the franchise. Unknown Worlds capped co-op at four players, but the Unreal Engine 5 jump introduces Nanite geometry streaming, volumetric water rendering, and a fluid simulation that all run authoritatively on the server. The result is a process that comfortably consumes 10 to 14 GB of RAM on a populated session, even with only four clients. CubeCoders AMP is the cleanest path to manage that on Windows Server: it handles the SteamCMD lifecycle, exposes RAM watchdogs, and gives you a clean web UI for clients who do not want to RDP into the box.

Prerequisites

• Windows Server 2022 with at least 16 GB RAM and 6 modern CPU cores (the fluid sim is memory bandwidth bound).
• CubeCoders AMP licensed and installed via the official MSI.
• UDP 27015 and UDP 27016 open in Windows Firewall.
• 50 GB of fast NVMe storage. The leviathan biome streams aggressively.

Step 1: Create the AMP Instance

Inside AMP's Instance Manager, choose Generic Module, name the instance Subnautica2, and let AMP allocate ports 27015 and 27016. AMP will provision the working directory under %PROGRAMDATA%\AMP\Instances\Subnautica2.

$ampinstmgr CreateInstance Generic Subnautica2 ADS01 0.0.0.0 8081 +Module Generic
$ampinstmgr StartInstance Subnautica2

Step 2: Install via SteamCMD

AMP's Generic module ships with a SteamCMD helper. Point it at the Subnautica 2 dedicated server app ID and let it pull the binaries.

$steamcmd +force_install_dir ./Subnautica2 +login anonymous +app_update 3380540 validate +quit

Step 3: Configure the Co-Op Session

$[/Script/Subnautica2.SubnauticaGameSession]
$SessionName=Aurora Survivors
$MaxPlayers=4
$ServerPassword=REPLACE_LONG_PASSWORD
$AdminPassword=REPLACE_ADMIN_PASSWORD
$
$[/Script/Subnautica2.WorldStreaming]
$StreamingPoolMB=4096
$NaniteCacheMB=2048
$FluidSimQualityLevel=2

Step 4: Launch Command

$Subnautica2Server.exe -log -Port=27015 -QueryPort=27016 \
$  -SteamServerName="Aurora Survivors" -MaxPlayers=4 \
$  -SaveInterval=300 -unattended

Step 5: Memory Aware Restart

Schedule a daily restart at 06:00 plus a memory triggered restart whenever the working set crosses 13 GB. The fluid simulation slowly leaks under sustained play.

$Trigger: Time of day -> 06:00 daily
$Action: Stop Instance, Start Instance
$
$Trigger: Instance memory usage exceeds 13312 MB for 5 minutes
$Action: Send in game broadcast "Restarting in 60s", Stop, Start

Performance and Tuning

• Use NVMe storage. Nanite streaming stalls visibly on SATA SSDs in the dunes biome.
• Lower FluidSimQualityLevel to 1 if your RAM budget is below 12 GB. The visual delta is small, the CPU savings are large.
• Pin the process to specific cores with AMP's affinity setting if the host runs other workloads.
• Cap autosave intervals at 5 minutes. The save serialization stalls the tick on UE5 builds.

Conclusion

Subnautica 2's small player cap belies a heavy server. With AMP handling lifecycle, SteamCMD updates, and memory aware restarts, a four player crew can run a multi week save without manual intervention. Treat the fluid simulation as the dominant resource budget and the rest follows.