Learn how to show the Microsoft Flight Simulator FPS counter, read MainThread, GPU and frame-time data, and identify what is limiting performance.
On PC, enable Developer Mode in Microsoft Flight Simulator, open the DevMode menu bar and select Options > Display FPS. The overlay shows frame rate, frame time and the active bottleneck. Read sustained Limited by MainThread as CPU-side pressure and Limited by GPU as graphics-card pressure.
How to display the MSFS FPS counter on PC
- Open the simulator settings. In Microsoft Flight Simulator 2020, go to
Options > General Options > Developers. In MSFS 2024, openSettings > Advanced Optionsand find Developer Mode. The settings search is the quickest route if an update has rearranged the categories. - Enable Developer Mode. Apply or save the change if the simulator presents that option.
- Open the DevMode menu bar. Move the pointer to the top of the screen if the bar is hidden, then select
Options > Display FPS. - Close the counter when finished. Select
Display FPSagain, and disable Developer Mode if you do not need its other tools.
The built-in developer FPS counter is a PC feature. Retail console versions, including Xbox and the PlayStation 5 release of MSFS 2024, do not expose the same DevMode overlay. A television or monitor may report its refresh or input rate, but that does not identify the simulator's CPU or GPU bottleneck.
How do you interpret the MSFS FPS counter?
The most useful readings are the frame times and the limiter label, not the FPS number alone. Watch them for at least several seconds because a label that flashes during a camera change or scenery load is not necessarily the persistent bottleneck.
| Reading | What it means | How to use it |
|---|---|---|
| FPS | Frames rendered each second | Higher is smoother, but consistency matters more than a brief maximum. |
| Frame time | Time needed to produce one frame, measured in milliseconds | Lower is better: 33.3 ms is about 30 FPS, 25 ms is 40 FPS and 16.7 ms is 60 FPS. |
| MainThread | CPU-side simulation, traffic, object preparation and aircraft systems | A persistently higher MainThread time indicates a CPU-side limit. |
| GPU | Graphics processing time | A persistently higher GPU time indicates that resolution or visual effects are limiting performance. |
| Other thread labels | Rendering, interface or cockpit-interaction work | Investigate these only when the same label remains dominant during normal flight. |
The CPU and GPU work overlap, so do not add their frame times together. The slower stage normally controls the delivered frame rate.
What does “Limited by MainThread” mean?
Limited by MainThread means the simulator's main CPU thread cannot prepare frames as quickly as the GPU could display them. Overall CPU usage may still look low because one heavily loaded logical processor can hold back the entire simulation.
Reduce Terrain Level of Detail first, then examine Objects LOD, road and airport vehicles, ships, AI or live traffic, and glass-cockpit refresh rate. Complex aircraft and detailed airports can impose a fixed CPU load that no resolution change will solve. Our settings guide matches individual options to CPU, GPU and VRAM pressure.
What does “Limited by GPU” mean?
Limited by GPU means the graphics card is taking longer than the CPU to complete each frame. Lower render scaling or output resolution first; clouds, shadows, reflections, ambient occlusion and anti-aliasing choices are the next settings to test.
If the panel also shows graphics memory close to its available budget, reduce texture demands and check high-resolution scenery or aircraft add-ons. VRAM exhaustion can produce stutters and poor frame times even when the GPU's average utilisation does not explain the whole problem.
What do RdrThread, CoherentGT and Manipulators mean?
These labels identify narrower CPU-side tasks. RdrThread concerns render submission, CoherentGT or similar UI labels usually point to cockpit displays and toolbar interfaces, and Manipulators concerns cockpit interaction. Close unused toolbar panels and pop-out instruments, stop moving the pointer, and compare cockpit and external views before changing global settings.
What FPS and frame time should you aim for?
There is no single correct target, but stable delivery should take priority over an average that continually swings up and down. A consistent 30 FPS can feel better than an average of 45 FPS with repeated spikes above 40 ms.
- 30 FPS: approximately 33.3 ms per frame; usable for slower flying when frame pacing is steady.
- 40 FPS: 25 ms per frame; a useful target with compatible variable-refresh displays or frame generation.
- 60 FPS: approximately 16.7 ms per frame; smoother camera movement and control response, but substantially more demanding.
- VR: use a target compatible with the headset's refresh and reprojection modes. Desktop FPS targets do not transfer directly to VR.
If V-Sync or another limiter is holding the simulator at exactly 30, 40 or 60 FPS, the displayed limiter label becomes less useful because the pipeline may be waiting deliberately. Disable the cap while diagnosing performance, then use our advice on choosing an MSFS 2024 frame-rate cap.
Frame generation can also make two counters disagree. The developer panel measures the simulator's rendering pipeline and may not include frames inserted afterwards, so generated output can look smoother without reducing the underlying MainThread time or control latency. When setting AutoFPS from a measured baseline, use the native reading and the persistent MainThread or GPU limit.
How should you test an MSFS performance change?
- Choose a repeatable scene. Use the same aircraft, airport, runway, weather, time and cockpit view.
- Let the scene settle. Scenery streaming, shader compilation and aircraft initialisation can distort the first readings.
- Record FPS and frame times. Check both the parked cockpit and an external view; they often expose different bottlenecks.
- Change one setting. Several simultaneous changes make it impossible to identify what helped.
- Retest a demanding arrival. A cruise result alone does not represent a large airport with traffic and detailed scenery.
For a fuller baseline procedure, including how to separate CPU and GPU limits before lowering image quality, follow our repeatable MSFS 2024 performance-tuning process.
Why is the FPS counter missing or misleading?
A missing counter usually means Developer Mode was not applied, while a misleading reading normally comes from testing during loading, frame generation or an active FPS cap.
- If the DevMode bar is absent, confirm Developer Mode is enabled and move the pointer to the top edge of the simulator window.
- If
Display FPSis missing, restart the simulator after enabling Developer Mode. - If the reading is locked to a precise value, check V-Sync, the simulator's frame-rate setting and any driver-level limiter.
- If an external overlay disagrees, determine whether it is counting generated output frames rather than native rendered frames.
- Ignore isolated red spikes while changing views, opening menus or loading scenery; diagnose a label only when it persists in normal flight.