Learn why MSFS add-ons reduce FPS, isolate the exact culprit, and fix CPU, GPU, VRAM, aircraft, scenery and traffic bottlenecks.
Add-ons reduce FPS in Microsoft Flight Simulator when they add more work than the main thread, GPU, VRAM or system memory can handle. Fix it by measuring the bottleneck, testing with all third-party content disabled, restoring packages in small batches, then reducing the specific scenery, aircraft, traffic or texture load responsible.
Where add-on FPS goes
Every active add-on consumes one or more finite performance budgets, and the slowest part of the frame determines the final FPS. A powerful GPU cannot compensate for an aircraft or traffic package that has saturated the CPU's main thread.
- Main-thread load: Complex aircraft systems, glass displays, AI traffic, airport animations and large numbers of scenery objects all require CPU time.
- GPU load: Detailed models, lighting, shadows, reflections, transparent surfaces and dense scenery increase rendering work.
- VRAM and system memory: High-resolution liveries, airport textures and large aircraft packages can exhaust available memory, causing severe drops, pauses or texture swapping.
- Storage and streaming: Large packages, duplicate assets or slow storage usually cause stutters and delayed loading rather than a steady reduction in FPS.
Two add-ons may run well separately but perform badly together. A complex airliner, detailed airport, traffic injector and nearby city enhancement can all demand resources during the same approach. Overlapping airport or scenery packages may also load duplicate objects rather than simply replacing one another.
Which add-ons have the biggest FPS impact?
Complex aircraft, detailed airports and high-density traffic usually have the largest effect, but file size alone is a poor predictor of performance.
| Add-on type | Typical bottleneck | Common clue |
|---|---|---|
| Study-level or systems-heavy aircraft | Main thread, displays and scripts | FPS falls mainly in the cockpit or improves with a default aircraft |
| Detailed airports and city scenery | Main thread, GPU and VRAM | Performance deteriorates as the airport or city comes into view |
| AI traffic packages | Main thread and memory | FPS changes sharply with traffic density or at major hubs |
| 4K or 8K liveries and texture packs | VRAM | Texture swapping, pauses or poor performance at high display resolutions |
| Mesh and regional enhancement packages | CPU, memory and streaming | The problem is confined to a particular region |
Simple liveries, sound replacements and small object packages often have little measurable effect when built efficiently. Conversely, a small utility can be expensive if it runs frequent scripts or causes an incompatibility.
How do I find the add-on causing low FPS?
A clean baseline followed by a binary search is the fastest reliable way to identify a performance-heavy package.
- Create a repeatable test. Use the same aircraft, airport, runway, cockpit view, weather preset and traffic conditions. Let the flight settle before recording the result.
- Identify the limiting resource. On PC, use the simulator's performance display and compare frame time as well as FPS. Our explanation of how to read the MSFS FPS and frame-time counters shows what MainThread and GPU limitations mean.
- Establish a clean baseline. Close the simulator and move or rename the contents of the PC
Communityfolder rather than deleting them. Disable separately installed Marketplace or optional packages through the simulator's content interface; an emptyCommunityfolder does not disable those. - Repeat the identical test. A substantial recovery points to an add-on or interaction between add-ons. If performance is unchanged, investigate simulator settings, drivers, thermal throttling and the base aircraft or scenery instead.
- Restore packages in halves. Add back half the disabled content, restart Microsoft Flight Simulator and repeat the test. Continue dividing the failing group until one package remains.
- Check for combinations. Test the suspected package alone, then with aircraft, traffic and overlapping scenery restored. If it performs well alone, the actual fault is a conflict or combined workload.
- Verify compatibility and options. Install the package's supported update, remove duplicate airports, confirm required dependencies and select lower-resolution textures or reduced-detail variants where supplied.
Change only one variable per run. Frame Generation can increase displayed FPS, but it cannot remove a main-thread bottleneck and may obscure comparisons unless it remains in the same state throughout every test.
MSFS 2020, MSFS 2024 and console differences
The same isolation method works in both PC versions, although the location of Community depends on the store edition and any custom package path selected during installation. Do not copy a folder path blindly from an old guide.
Xbox users, and PlayStation users of Microsoft Flight Simulator 2024, cannot perform the PC folder test. Disable or uninstall removable add-on content through the simulator's installed-content interface, restart it, and reproduce the same flight.
Match the fix to the bottleneck
Fix the saturated resource rather than reducing unrelated settings across the board.
| Limit | Effective fixes | Usually ineffective |
|---|---|---|
| Main thread | Reduce Terrain or Object Level of Detail, AI traffic, parked aircraft, airport activity and glass-cockpit refresh load; use lighter aircraft or scenery options | Lowering render resolution when the GPU already has spare capacity |
| GPU | Reduce render scaling, cloud quality, shadows, reflections or other graphics-heavy settings; use an appropriate upscaling mode | Removing CPU-heavy traffic when the performance display shows a pure GPU limit |
| VRAM or system memory | Use lower-resolution textures and liveries, remove duplicate scenery, reduce texture quality if necessary and close memory-heavy background applications | Increasing traffic or object detail after an allocation warning |
| Storage or streaming | Keep packages on fast local storage, remove broken links or duplicates, and test rolling-cache behaviour | Treating brief loading pauses as a constant GPU limitation |
If Microsoft Flight Simulator 2024 reports low memory resources, follow our specific memory and VRAM pressure checks before lowering every graphics option. Memory exhaustion can make an otherwise smooth add-on collapse abruptly rather than lose a few frames gradually.
Prefer the add-on's own configuration choices when available. Disabling optional static aircraft, animated people, interior modelling or ultra-resolution textures usually preserves more visual quality than reducing global simulator settings for every flight.
Why does FPS only collapse near airports or after long flights?
Location-specific drops usually indicate combined scenery load, while deterioration over time points more strongly to memory growth, traffic accumulation, aircraft scripts or cache behaviour.
Near a detailed airport
An add-on airport is often only one part of the load. The simulator may simultaneously render the aircraft cockpit, terminal interiors, ground traffic, parked aircraft, AI models, nearby photogrammetry and weather effects. Test the airport with a default aircraft and traffic disabled before blaming the scenery alone; our combined-load checks for landing-area FPS drops cover this case in detail.
Later in the flight
A gradual decline that resets when the simulator restarts can indicate accumulated memory or a package that fails to release resources correctly. A restart treats the symptom, not the cause. Compare the same route without the aircraft, traffic and scenery packages, then use the long-flight FPS troubleshooting sequence to separate add-on behaviour from cache and simulator issues.
Do load order, rolling cache or reinstalling fix add-on FPS?
These fixes help only when the underlying problem involves a conflict, corrupted data or incorrect package priority; they do not make an inherently demanding add-on inexpensive.
- Load order: Adjust it only when two packages replace the same airport, terrain or navigation data. Priority controls which asset wins, but it does not remove the workload of every active package.
- Rolling cache: Clear or recreate it when streamed scenery is corrupted or producing pauses. It rarely fixes steady low FPS caused by cockpit systems or AI traffic.
- Reinstallation: Use it after confirming damaged or incomplete files. Reinstalling the same healthy package will not reduce its object count, texture resolution or script load.
Keep the add-on when its unique features justify a manageable cost and it offers useful detail controls. Replace or remove it when the clean baseline restores performance, no adjustable option addresses the actual bottleneck, and the package remains problematic after compatibility and conflict checks.