Learn which flight simulator add-ons reduce FPS, how to find the culprit, and when to change settings, disable scenery or remove an add-on.
Yes. Flight simulator add-ons can reduce FPS, increase stuttering and lengthen loading times, but the impact depends on what they add and where the bottleneck lies. Complex aircraft, detailed airports, AI traffic, weather engines and high-resolution scenery are usually heavier than simple liveries, static objects or sound packs.
Across general-purpose simulators such as Microsoft Flight Simulator, FSX, X-Plane and Prepar3D, the principle is the same: add-ons consume CPU time, graphics resources, memory or storage bandwidth. A mistake we see constantly is blaming the total add-on count when the active workload and conflicts matter more.
Which flight simulator add-ons reduce FPS most?
Complex aircraft, busy airports and AI traffic are the add-ons most likely to reduce FPS, especially when used together.
| Add-on type | Typical performance effect | Main reason |
|---|---|---|
| Complex aircraft | Medium to high | Systems simulation, cockpit displays, avionics and custom code can overload the CPU main thread. |
| Detailed airports and cities | Medium to high near the covered area | Extra objects, lights, animations, textures and draw calls increase CPU, GPU and VRAM demand. |
| AI traffic | Medium to high at busy airports | Every aircraft adds flight logic, models, textures, animations and draw calls. |
| Weather and cloud enhancements | Low to high | Cloud rendering can be GPU-heavy, while external weather utilities may also perform background processing. |
| Photographic, orthographic or high-resolution scenery | Usually low to medium FPS loss, with possible stutters | Large textures place pressure on VRAM, RAM, storage and scenery loading. |
| Global plugins and utilities | Varies widely | Some run continuously, poll simulator data or draw overlays even when their interface is hidden. |
| Liveries and sound packs | Usually negligible | They add little processing, although large textures or AI model matching can increase memory use. |
Performance costs also stack. A complex airliner may run well at a default airport, and a detailed airport may run well in a simple aircraft, yet the combination can overwhelm the main thread or available VRAM. Payware is not automatically heavier than freeware, and file size alone does not predict FPS.
Do installed add-ons slow the simulator when they are not in use?
No: an installed add-on does not automatically consume resources throughout every flight. Its scope and loading behaviour determine when it matters.
- Local airport scenery normally has its greatest effect when the airport or surrounding tiles are loaded.
- An unselected aircraft usually does not affect in-flight FPS unless its model is being used for AI traffic or multiplayer model matching.
- Global plugins, traffic tools and weather utilities may run for the whole session and can affect flights anywhere.
- Large add-on libraries can increase start-up, package scanning and menu loading times without reducing FPS once airborne.
- Overlapping scenery packages can create duplicated objects, elevation conflicts, flashing surfaces and avoidable processing.
The loading system differs by simulator. X-Plane plugins placed in Resources/plugins commonly load globally, while scenery in Custom Scenery is location-dependent. FSX and Prepar3D use activated scenery areas and separately loaded modules. Microsoft Flight Simulator packages can contain local scenery, aircraft or globally active code.
How do I find which add-on is causing low FPS?
The reliable method is an A/B test using the same saved flight and conditions, followed by a binary search through the installed add-ons.
- Create a repeatable baseline. Use the same aircraft, airport, runway, cockpit view, weather preset and traffic level. Live weather and online traffic vary, so disable them temporarily if possible. Record FPS and frame time after the flight has settled.
- Disable the suspected content. Close the simulator first. On PC versions of MSFS, move third-party packages out of the
Communityfolder or disable managed content through the simulator. Our MSFS 2024 Community-folder isolation checks cover this process and the related performance settings. - Use the simulator-appropriate method. In X-Plane, move a third-party plugin or scenery package outside the simulator directory. In FSX or Prepar3D, disable scenery through the Scenery Library and use the supplied uninstaller for aircraft or modules. Do not delete shared libraries that other packages require.
- Run the identical test again. A higher average FPS points to sustained load; smoother frame times with similar FPS indicate that the add-on was causing intermittent stalls.
- Add packages back in halves. If many add-ons are involved, enable half the group and test again. Repeating this process finds the culprit much faster than testing packages one by one.
- Confirm the result. Test the suspected add-on alone and then with the aircraft, airport or traffic package normally used beside it. If only the combination causes trouble, the problem is cumulative load rather than one defective product.
On Xbox and PlayStation versions of Microsoft Flight Simulator, use the simulator’s content controls; PC folder instructions do not apply. For older Microsoft simulators, our FSX-specific performance tuning advice explains why scenery, traffic and complex panels often need different compromises.
Should I remove the add-on or change simulator settings?
Remove or disable an add-on when it performs badly by itself, conflicts with other scenery, is incompatible with the simulator build or causes crashes; adjust settings when it is simply demanding in a known heavy scenario.
- CPU or main-thread limit: reduce AI traffic, airport activity, object density or other CPU-heavy features before lowering texture resolution. In MSFS 2024, use the developer performance display where available and follow our guide to diagnosing a main-thread limitation.
- GPU limit: reduce render resolution, cloud quality, shadows or other graphics-heavy settings. Removing a CPU-heavy traffic utility will not fix a saturated GPU.
- VRAM or RAM pressure: lower texture quality, avoid overlapping high-resolution scenery and load only the packages needed for the flight.
- Storage-related pauses: reduce very large scenery installations or move frequently used content to faster storage rather than cutting unrelated graphics settings.
- One-location problem: keep the add-on and use lighter traffic or graphics settings at that airport instead of degrading every flight.
Why can an add-on cause stutters without lowering average FPS?
An add-on can produce uneven frame times while leaving the reported average FPS almost unchanged. Common causes include scenery tiles loading, textures moving between system memory and VRAM, autosave utilities, traffic injection and cockpit displays updating at intervals.
Judge performance by smoothness and frame-time consistency, not only the FPS counter. If MSFS 2020 pauses despite an acceptable average frame rate, work through our MSFS 2020 stutter and micro-pause checks.
There is no need to strip every add-on from a simulator. Keep packages organised, avoid duplicate scenery, activate only what the flight needs and test after installing anything that changes aircraft systems, airports, traffic, weather or global simulator behaviour.