Learn why GSX can reduce FPS in MSFS 2024, how to identify main-thread or VRAM limits, and which GSX and simulator settings to change first.
Yes. GSX Pro can reduce FPS in Microsoft Flight Simulator 2024, mainly while passengers, baggage vehicles and other animated services are active. The loss comes from additional main-thread, GPU and VRAM work, not a fixed frame-rate cap. Reduce visible passengers and simultaneous services first, then check traffic, airport scenery and memory use.
This guidance applies to PC because GSX Pro is a PC add-on. Xbox and PlayStation users cannot run it; similar apron slowdowns on those platforms come from the simulator, aircraft, traffic or airport scenery instead.
Does GSX lower FPS all the time?
GSX usually has its largest performance impact during boarding, deboarding, catering, baggage handling and pushback. Each operation adds animated people or vehicles, pathfinding, sounds, lighting and extra draw calls. The effect is amplified at a detailed airport with a complex airliner and dense AI traffic.
Idle GSX normally costs much less. FPS should recover after its vehicles and walking passengers leave, unless seated passengers remain in the aircraft, the toolbar panel is still open, a service is stuck or the system has run short of VRAM.
How can I test whether GSX is causing the FPS loss?
A controlled comparison at the same gate is the only reliable way to separate GSX load from the airport, aircraft and traffic around it.
- Create a stable baseline. Load at a gate, let scenery and traffic settle, keep the same aircraft, weather, camera and time of day, and do not request any services yet.
- Measure frametime as well as FPS. Use the simulator's performance display to identify the limiting component. If Frame Generation is enabled, compare base frametime rather than relying only on the generated FPS figure.
- Start one GSX operation at a time. Test boarding, baggage, catering and pushback separately. Note whether the drop begins when vehicles arrive, walking passengers appear or seated passengers populate the cabin.
- Close the GSX toolbar panel. Leaving an in-game panel open or popped into another window can introduce a separate UI-rendering penalty. Our explanation of toolbar and pop-out panel FPS losses covers that issue.
- Run an unloaded comparison. Disable GSX through its supported installer or add-on management method, restart MSFS 2024 and repeat the same scenario. Merely avoiding a service request is not the same as unloading the add-on.
- Classify the bottleneck. Use the result to choose settings instead of lowering everything indiscriminately.
| Observed behaviour | Likely cause | First change to make |
|---|---|---|
| FPS falls as passengers appear | Animation, draw calls or seated cabin models | Disable seated passengers and lower visible passenger density |
Limited by MainThread appears | GSX activity combined with traffic, aircraft systems and airport objects | Reduce simultaneous services, traffic and Object Level of Detail |
| GPU frametime rises or VRAM fills | Passenger models, textures, lighting and detailed scenery | Reduce texture-heavy features and cabin passengers |
| Only one airport is affected | Scenery overlap, jetway configuration or abnormal vehicle routing | Check that airport's GSX exclusion and profile |
| Drop occurs only while the GSX panel is visible | Toolbar or pop-out rendering | Close the panel after requesting the service |
Modest total CPU usage in Windows does not rule out a main-thread limit. One critical simulation thread can be saturated while the processor's overall percentage still looks low.
Which GSX settings improve performance most?
Passenger rendering is usually the first GSX feature to reduce when FPS drops during boarding or remains low afterwards.
Changes inside GSX
- Disable seated cabin passengers. This is the best first test with supported aircraft because those models can remain loaded for the entire flight.
- Lower visible passenger density. Use the density or visible-passenger control exposed by your installed GSX build. Do not falsify a SimBrief passenger count merely to improve FPS; reduce what is rendered instead.
- Sequence ground services. Avoid running every available vehicle and passenger operation simultaneously when using a CPU-heavy aircraft or airport.
- Close the GSX menu after use. The service continues after the toolbar panel is closed.
- Update GSX and its components through the supplied installer. Do not manually move or delete its linked packages, because a partial installation can create missing models or repeated loading problems.
Accelerated boarding shortens how long the load lasts, but it does not necessarily reduce the peak number of objects being processed. Lower density is the better choice when peak frametime is the problem.
Changes inside MSFS 2024
- When main-thread limited: reduce AI or live traffic, ground aircraft, airport vehicle density and Object Level of Detail. The simulator's Airport Vehicle Density setting controls native traffic, not GSX's own vehicles, but lowering it reduces the combined apron workload. Use our main-thread diagnosis and setting priorities if the developer display reports that limit.
- When GPU or VRAM limited: reduce texture resolution, render scaling, shadows or other GPU-heavy options selectively. High-resolution aircraft liveries, detailed terminals and cabin passengers can exhaust memory together; these VRAM reduction steps preserve the most useful visual detail.
- Remove duplicated activity: disable either an airport's own animated passengers and service vehicles or the equivalent GSX feature. Running both rarely improves the scene enough to justify the extra load.
- Check jetway exclusions: third-party airports with custom jetways should be excluded from GSX's replacement system where required by the scenery. Duplicate or incompatible jetway handling can add clutter and cause operational faults.
Why does FPS stay low after boarding or pushback?
Persistent FPS loss usually means something remains rendered or the flight has crossed a CPU, RAM or VRAM threshold.
- Seated passengers intentionally remain aboard after boarding.
- A vehicle or passenger route may be stuck because the stand or airport profile is unsuitable.
- The GSX toolbar window may still be open.
- Textures and models may remain allocated until the flight or simulator is reloaded.
- A busy destination airport may have pushed an already full VRAM budget over its limit.
If vehicles loop, bunch together, repeatedly respawn or take abnormal routes, test the airport without its custom GSX profile and verify its scenery exclusion. A profile is not normally an FPS problem by itself, so changing profiles blindly will not fix an ordinary GPU bottleneck.
When parked with no pushback active, restart GSX or Couatl using its supplied control and watch whether performance recovers. Do not terminate it during pushback, because GSX may be controlling the aircraft's movement. If restarting GSX changes nothing, reload without GSX and repeat the controlled test.
Which common fixes should I avoid?
Changes unrelated to the measured bottleneck waste image quality and can make GSX harder to troubleshoot.
- Do not cut render scaling when the display says
Limited by MainThread; that primarily reduces GPU load. - Do not assume Airport Vehicle Density controls GSX vehicles.
- Do not compare generated FPS in one test with native FPS in another.
- Do not assign arbitrary CPU affinity or extreme process priority to Couatl or MSFS.
- Do not uninstall every airport profile because one stand has bad routing; isolate the affected airport and gate first.
If the slowdown follows visible passengers or active GSX vehicles, tune GSX first. If performance is almost identical with GSX fully disabled, the real limit is the aircraft, airport, traffic or simulator settings rather than GSX itself.