Improve Garry's Mod Server Performance

This guide shows you how to optimize your Garry's Mod server performance. GMod runs on the Source engine, which was released back in 2004 – with the right settings you can still get the most out of your server, especially with many players and addons.

1. Optimize Tickrate

The tickrate determines how often per second the server calculates the game world. The default is 66 ticks – for most servers, 33 ticks is completely sufficient and halves the CPU load:

# In server.cfg
sv_minrate 20000
sv_maxrate 50000
sv_mincmdrate 33
sv_maxcmdrate 33

• sv_minrate / sv_maxrate: Bandwidth per player in bytes/second. Lower values relieve the network
• sv_mincmdrate / sv_maxcmdrate: Tickrate. 66 = default, 33 = halved (recommended for large servers)

2. Adjust Network Settings

# In server.cfg
sv_parallel_packentities 1
sv_parallel_sendsnapshot 1
net_queued_packet_thread 1
net_splitpacket_maxrate 50000

• sv_parallel_packentities: Processes entities in parallel – makes better use of multi-core processors
• sv_parallel_sendsnapshot: Sends player updates in parallel instead of sequentially
• net_queued_packet_thread: Outsources network packets to a separate thread

3. Reduce and Optimize Addons

Addons are the biggest performance drain in GMod. Every addon loads Lua scripts, models and textures:

• Only install needed addons: Every addon costs RAM and CPU – uninstall everything that isn't actively used
• Identify large addons: Addons with many models (vehicles, weapons, NPCs) put the most strain on the server
• Organize addons in collections: With a Workshop Collection you keep track and can quickly test which addons cause performance problems
• Find faulty addons: Addons with Lua errors cause constant error messages in the console – this eats CPU. Remove or update faulty addons

4. Set Sensible Player Limits

• Reduce maxplayers: Each player increases network and CPU load. Fewer slots = more stable performance
• Limit props per player: Too many spawned objects (props) bring any server to a halt. Typical limits:

  # With ULX Admin Mod
  ulx setlimit props 50

• Limit NPCs and ragdolls: Every physically simulated entity eats CPU. Automatically clean up with addons like "Prop Protection" or "Cleanup"

5. Set Up Regular Cleanups

GMod servers accumulate hundreds of leftover props, ragdolls and vehicles over time. Automatic cleanup scripts help:

# In server.cfg – remove props and ragdolls every 10 minutes
sv_airaccelerate 10

# With ULX – automatic cleanup every 300 seconds
ulx setcleantime 300

6. Optimize Maps

• Choose smaller maps: Large maps with many details (gm_bigcity, rp_downtown) put more strain on the server than small maps (gm_construct, gm_flatgrass)
• Check map-specific entities: Some maps spawn hundreds of NPCs or physical objects – this eats CPU right from the start
• Use FastDL: With FastDL (Fast Download), maps and addons are loaded from a separate web server – this relieves the game server

7. Restart Server Regularly

The Source engine is known for memory leaks – after a few hours of runtime, the server becomes noticeably slower:

# Automatic restart via cronjob (Linux)
0 4 * * * /path/to/gmod/start-server.sh

# Or via systemd service with automatic restart
[Service]
Restart=always
RestartSec=10

A daily restart at 4 AM keeps the server fresh without disturbing players.

8. Optimize SRCDS Startup Parameters

# Additional performance parameters for the startup script
-nobots +exec server.cfg -tickrate 33 -threads 4 -high

• -nobots: Disables AI bots – saves CPU
• -tickrate 33: Limit tickrate to 33 (default: 66)
• -threads 4: Number of CPU threads used (adjust to your cores)
• -high: Sets the server process to high priority (Windows only)

9. Set Up FastDL (External Download Server)

FastDL outsources the downloading of maps and addons to a separate web server. This massively relieves the game server, especially when new players join:

1. Create a folder on a web server (e.g. your webspace)
2. Copy all addons and maps there
3. Enter in server.cfg:

   sv_downloadurl "http://your-domain.com/fastdl/"
   sv_allowdownload 1
   sv_allowupload 1

10. Hardware Tips

• CPU: High single-core performance is more important than many cores. The Source engine mainly uses one core
• RAM: With many addons and players, RAM usage increases quickly. 6-8 GB minimum for servers with 64 slots
• Storage: NVMe SSD significantly reduces the loading time of maps and addons
• Network: Stable connection with at least 100 Mbps, especially when many players download addons simultaneously

Quick Checklist

1. Reduce tickrate to 33 (sv_mincmdrate 33)
2. Enable sv_parallel_packentities and sv_parallel_sendsnapshot
3. Uninstall unnecessary addons
4. Limit props and NPCs per player
5. Set up automatic cleanup every 5-10 minutes
6. Set up FastDL for maps and addons
7. Restart server daily (cronjob or systemd)
8. Use startup parameters -tickrate 33 and -high