Last updated: September 18, 2026
SCP: Secret Laboratory is more sensitive to fast single-thread CPU than to large amounts of RAM, because rounds, AI, movement, and plugins all compete for timely simulation. This guide covers the settings and habits that keep a server running smoothly.
These live in config_gameplay.txt. Stop the server before editing, then start it again to apply the changes.
| Setting | Default | Effect |
|---|---|---|
max_players | 20 | Player limit. Lower it if the hardware cannot keep up. SCP:SL has no hard cap, so the practical limit is your CPU. |
server_tickrate | 60 | Simulation rate. Leave it at 60 for a healthy server; lowering it toward 30 can help a CPU-limited server at some cost to smoothness. |
ragdoll_cleanup_time | 120 | Seconds before a ragdoll is removed, in seconds. Lower it to reduce entity buildup; 0 keeps ragdolls forever. |
idle_mode_enabled | false | When true, the server drops to a low tickrate while nobody is connected, saving CPU on empty servers. |
idle_mode_tickrate | 1 | Tickrate used while idle mode is active. |
restart_after_rounds | 0 | Restart the server after this many rounds. 0 disables it; a value such as 15 counters the slowdown that builds up over long sessions. |
use_crypto_rng | true | Set to false to avoid the extra CPU cost of secure random numbers. |
config_gameplay.txt. Some third-party guides list generic keys that are not part of the real SCP:SL config, so verify before adding anything.
max_players: 20
server_tickrate: 60
ragdoll_cleanup_time: 60
idle_mode_enabled: true
restart_after_rounds: 15
use_crypto_rng: false
Adjust one value at a time and re-test, so you can tell which change actually helped.
SCP:SL, like many Unity servers, slows down gradually over a long uptime. A scheduled restart clears accumulated state. Setting restart_after_rounds automates this, or you can restart manually from the panel's Console page during a quiet moment.
max_players is the quickest free win.