How to improve FPS in Garry's Mod (PC)
Garry's Mod runs on Source Engine, a 2006 engine that in theory any modern PC can run without breaking a sweat. The problem is that almost nobody plays GMod "clean": real performance depends on which Steam Workshop addons the server (or your client) has installed, how many physics props have piled up on the map, and how much Lua code runs every tick. A DarkRP or sandbox creative server with months of activity can bring an RTX 4080 to its knees just as easily as a GTX 1050, because the bottleneck isn't your GPU: it's the CPU processing physics and scripts.
This is what you'd gain with a NVIDIA RTX 3050
Calculations based on our FPS model combined with the % gain of each setting (measured in public benchmarks).
1. Quick wins (no visual loss)
Start here. Each one adds a little, but together they give +38% free FPS.
Detalle de terreno (cl_detaildist)
Terrain detail (grass, small rocks) that Source draws over displacements consumes more than it appears on large maps like gm_flatgrass or open roleplay maps. Reducing the render distance is barely noticeable visually.
Colección de addons ligera
Every addon subscribed on Steam Workshop gets precached at startup, increasing loading times and RAM/VRAM usage even if you never use those props. Massive prop packs of dubious optimization are the number one cause of stuttering.
Sombras dinámicas de props
In scenarios with many physics props, each one casts its own dynamic shadow rendered separately. This scales poorly the more props there are on screen, exactly the typical situation in sandbox and large builds.
Decals de sangre y balas
On roleplay or combat servers (TTT, murder, DarkRP with weapons), blood and bullet decals accumulate on surfaces with no limit other than the one you set. Over long matches this adds silent but constant render overhead.
Límite de FPS
Source Engine has framerate-tied physics and network behavior in older versions of the engine; an unlimited fps_max can generate micro-stutters from tickrate variability in physics-heavy scenarios.
2. Medium impact settings
Here's where most of the FPS is. Minor visual impact, major performance impact.
Auditar colección de Workshop
Unlike most games, in GMod the most impactful optimization isn't in graphics but in your Workshop library. Addons with Lua scripts running on every Think() consume CPU constantly even when not actively used.
Elegir servidores con limpieza automática
Performance in multiplayer depends on the server far more than on the game itself: a poorly managed DarkRP with thousands of accumulated physics props makes even an i9 run at 20 FPS from the server's physics simulation.
Configuración de red (rate/interp)
On servers with 50+ players (common in DarkRP), a poorly configured network update rate generates CPU spikes on the main thread when processing network snapshots.
Limitar addons de post-procesado (PAC3)
PAC3 lets every player wear extremely heavy custom models and effects. On an RP server with 40 players, each with their own PAC3 outfit, per-player render cost multiplies non-linearly.
Renderizado multihilo (mat_queue_mode)
Source Engine doesn't always correctly detect the render parallelism available on modern CPUs. Forcing the multithreaded queue mode can better distribute load across cores.
3. Upscaling (DLSS / FSR / XeSS)
The biggest gain in the game. Compatible with almost any modern GPU.
Sin upscaling nativo
+0% FPSSource Engine (2006) doesn't natively support DLSS, FSR, or XeSS: there's no temporal upscaling implementation in the engine. On modern systems this doesn't matter for GPU, since almost no current hardware is resolution-limited in GMod.
FSR 1.0 forzado por driver
+3% FPSTechnically possible but provides practically nothing: being such a graphically light engine, render resolution is rarely the limiting factor. It only makes sense on very old GPUs or integrated graphics playing at 1440p/4K resolutions.
4. Tips by GPU
NVIDIA
- •Enable "Prefer maximum performance" mode in the NVIDIA control panel for GMod: the engine doesn't saturate the GPU and the driver sometimes aggressively lowers clocks by default.
- •Disable unnecessary Shader Cache or clear it if you notice stuttering when loading new props: GMod compiles many custom addon shaders on the fly.
- •Don't expect gains from DLSS or Frame Generation: they don't exist for this engine.
AMD
- •Use Radeon Chill with a moderate range instead of an unlimited fps_max to reduce power draw without perceptible loss of smoothness.
- •Check that Radeon Anti-Lag doesn't interfere with mods that modify input; in rare cases it generates micro-stutters in Source Engine.
- •There's no real native FSR here that adds FPS: prioritize CPU/server settings over GPU settings.
Sistema
- •Install GMod on SSD (ideally NVMe): with hundreds of subscribed addons, map loading times depend more on disk I/O than anything else.
- •Close Steam Workshop in the background and other overlays during long sessions on populous servers: every millisecond of CPU counts when the server is already saturating a core with physics.
- •Periodically review your Workshop collection and remove duplicate or abandoned addons.
5. Known game issues
Prop lag from unmanaged physics accumulation
On sandbox/DarkRP servers without active administration, physics props accumulate indefinitely because players rarely remove them. Every active prop participates in the engine's physics calculations, and that load scales non-linearly. It's only solved with automatic cleanup addons from the server admins.
Progressive memory leaks in long sessions
Sessions lasting several hours (common in RP) can accumulate memory leaks from poorly released Lua scripts in certain addons, especially HUDs and custom inventory systems.
Stuttering spikes when precaching new Workshop models
When entering a server with addons you don't have downloaded or updated, the client downloads and compiles those resources on the fly, generating freezes of several seconds.
6. Frequently asked questions
Why does Garry's Mod run badly on my PC if it's a 2006 game and I have a powerful GPU?▾
What is "prop lag" and how do I avoid it?▾
Is a high-end GPU worth it for playing GMod?▾
Why does the game have micro-stutters when entering a new server?▾
Want to know exactly how many FPS YOUR PC will get?
Enter your GPU and CPU in our calculator and measure the real impact of each setting.
Calculations based on consensus of technical sources and our own FPS model. More about our methodology →