Learn why Microsoft Flight Simulator FPS is low during cruise and how to fix main-thread, GPU, traffic, scenery-streaming and VRAM bottlenecks.
Microsoft Flight Simulator can have low FPS during cruise because altitude expands the visible terrain area, while complex aircraft, glass-cockpit displays, traffic, clouds and streamed scenery still consume CPU, GPU and VRAM resources. The cause is usually a main-thread, graphics or memory bottleneck, not simply the aircraft being airborne.
Why can FPS be worse at cruise altitude?
Cruise exposes a large terrain radius while the simulator continues running avionics, aircraft systems, weather and traffic. Looking down from altitude can therefore be more demanding than expected, especially with high Terrain Level of Detail, detailed cloud layers or a complex airliner.
Location also matters. Flying over an ocean with preset clear weather is not comparable to crossing a photogrammetry city beneath several cloud layers. Approaching a detailed destination can add another load spike even before the airport fills the windscreen.
A mistake we see constantly is assuming poor internet bandwidth directly causes sustained low FPS. Streaming trouble more often produces blurry ground textures, delayed scenery and intermittent stutters; our guide to diagnosing scenery streaming and rolling-cache problems covers that separate failure mode.
How do I identify the cruise FPS bottleneck?
On PC, enable Developer Mode and open Microsoft Flight Simulator’s built-in FPS display; its location and wording differ slightly between MSFS 2020 and MSFS 2024. The limiting-factor readout is more useful than GPU utilisation alone.
| What you observe | Likely bottleneck | Best first test |
|---|---|---|
Limited by MainThread | Terrain detail, traffic, avionics, aircraft systems or an add-on | Reduce Terrain LOD and traffic, then compare cockpit and external views |
Limited by GPU | Resolution, render scaling, clouds, anti-aliasing or other graphics load | Lower render scaling or Cloud Quality |
| Stutters with VRAM nearly full | Texture and scenery memory pressure | Reduce texture resolution and close GPU-heavy background programs |
| Cockpit FPS is much lower than external-view FPS | Glass displays, cockpit rendering or aircraft systems | Lower glass-cockpit refresh rate where offered and test a default aircraft |
| FPS sits at an exact value such as 30 | V-Sync, a frame limiter or a refresh-rate division | Temporarily remove the cap and retest |
If the display reports a CPU limit, use our main-thread optimisation steps for MSFS 2024 rather than lowering every graphics option. Many GPU settings barely affect a CPU-bound flight.
Which settings should I change first?
Change the settings that address the measured bottleneck, one group at a time. Randomly selecting a lower preset can damage image quality without fixing the limiting component.
- Create a repeatable test. Use the same aircraft, cockpit view, route area, weather and traffic conditions. Temporarily disable V-Sync or any FPS cap so it does not conceal the result.
- Test the aircraft. Compare cockpit and external views, then load a simpler default aircraft in a similar cruise situation. A large improvement points to avionics, aircraft systems or the add-on itself.
- Reduce CPU-heavy settings. Lower Terrain Level of Detail first, followed by live or AI traffic, ground aircraft and airport vehicle density. Traffic can consume main-thread time even when few aircraft are visible; see the traffic settings that recover CPU headroom.
- Reduce GPU-heavy settings. If the GPU is limiting, lower render scaling, output resolution or Cloud Quality. Upscaling can help at high resolution, but it will not repair a main-thread bottleneck.
- Check VRAM pressure. Reduce texture resolution if usage is close to the card’s capacity and stutters appear when turning the camera. Avoid running browsers, video playback or overlays that reserve significant GPU memory during the test.
- Run a clean add-on test. Temporarily disable third-party aircraft, scenery, traffic injectors and toolbar utilities. Reintroduce them by category rather than all at once.
Once the underlying frame rate is stable, restore a sensible FPS cap if desired. Frame generation may improve displayed smoothness on supported hardware, but it does not remove CPU spikes, exhausted VRAM or scenery-loading pauses.
Why does FPS get worse the longer the cruise lasts?
A progressive decline over several hours is different from FPS that is low as soon as cruise begins. Memory pressure, an add-on that accumulates work, traffic or scenery loading, and cache-related problems become more likely when performance never recovers after leaving a demanding area.
Restart the simulator and reproduce a comparable cruise scene. If performance returns immediately with the same settings, investigate accumulated memory use and add-ons before reducing image quality; our long-flight FPS deterioration checklist covers that pattern in detail.
What can console users test?
Console users can isolate the cause without the PC developer overlay by comparing a default aircraft, preset clear weather and disabled or reduced traffic against the problem flight. Fully restart the simulator between tests and temporarily remove third-party content associated with the route or aircraft.
Microsoft Flight Simulator 2020 is limited to PC and Xbox, while MSFS 2024 also runs on PlayStation 5. Console graphics controls are more restricted, so aircraft complexity, traffic, weather and installed content are the most practical variables to isolate.
Tune for the cockpit, route and weather you actually use—not the highest FPS seen in an external view over empty terrain. Consistent frame times at cruise are more valuable than a higher average interrupted by main-thread or scenery-loading spikes.