Change flight sim settings or upgrade your PC? Diagnose CPU, GPU, VRAM, RAM and stutters first, then spend only where testing proves it.
For PC flight simulators in general, change settings before upgrading hardware. Build a repeatable test, inspect CPU and GPU frame times, then lower only the settings tied to the bottleneck. Upgrade when those changes prove the limiting component and the visual quality or traffic compromises needed for smooth, consistent performance are unacceptable.
A mistake we see often is buying a faster graphics card because the FPS is low when the simulator is actually waiting on one CPU thread. Average FPS is equally deceptive: uneven frame delivery, add-on pauses and poor display synchronisation can make a nominally fast simulator feel choppy.
Diagnose the bottleneck before spending money
A repeatable A/B test tells you more than a recommended-specification chart or a single FPS reading.
- Create a representative test. Use the same aircraft, airport, weather, traffic, cockpit view and time of day for every run. Test somewhere demanding that reflects how you fly; an empty runway in a default aircraft can conceal the limitation you encounter at a detailed hub.
- Expose the uncapped performance. For diagnosis, temporarily disable V-Sync, frame caps, dynamic resolution and frame generation. These features are useful in normal play, but they can hide which component is finishing each frame last. Restore an appropriate cap after testing.
- Read CPU and GPU frame times. Use the simulator's built-in performance display where available. Microsoft Flight Simulator 2020 and 2024 can identify limits such as
MainThreadand GPU, while other simulators may show separate CPU and GPU frame times. Total CPU utilisation can look modest even when one logical core is saturated. - Run a GPU test. Lower display resolution or render scaling substantially without changing anything else. A large improvement points towards a GPU limit. Little or no change suggests a CPU limit, an active cap or a different source of stuttering.
- Run a CPU test. Restore resolution, then reduce terrain and object detail, autogen or scenery density, AI traffic, road traffic and cockpit display refresh rates. A meaningful improvement indicates pressure on the main simulation thread.
- Establish a clean baseline. Repeat the test with a default aircraft and airport, no external traffic or weather utilities, and third-party content disabled. For Microsoft Flight Simulator, this includes packages in the
Communityfolder; other simulators have equivalent scenery and plug-in locations. - Watch a longer session. If performance starts well and then deteriorates, check temperatures, clock speeds, committed memory and disk activity. Thermal throttling, memory paging and a faulty utility should be corrected before hardware is replaced.
| Likely limit | Evidence to look for | Change first | When an upgrade makes sense |
|---|---|---|---|
| Main CPU thread | The overlay reports a main-thread limit, GPU usage drops, and reducing resolution barely changes performance. | Lower terrain or object detail, scenery density, AI traffic and complex cockpit display refresh rates. | Representative flights require unacceptable reductions to traffic, scenery or aircraft complexity. |
| GPU | GPU frame time is highest and reducing resolution or render scaling produces a clear gain. | Reduce render scaling, clouds, shadows, reflections, ambient occlusion and anti-aliasing quality. | Your target resolution and image quality cannot be maintained at a stable frame rate. |
| VRAM | Panning at detailed airports causes texture swapping or severe hitches near the card's practical memory limit. | Lower texture resolution, render resolution and memory-heavy scenery options. | Normal aircraft and airports repeatedly exceed available graphics memory. |
| System RAM | Committed memory approaches physical capacity and Windows begins paging heavily, often during long sessions. | Close background software, test without suspect add-ons and leave the Windows page file enabled. | Normal use creates repeatable memory pressure after software faults have been excluded. |
| Storage | Pauses coincide with asset loading or sustained disk activity, especially when the simulator is installed on a hard disk. | Test without the affected scenery and move a hard-disk installation to an SSD. | The storage device is demonstrably delaying asset delivery; storage will not fix sustained CPU- or GPU-bound FPS. |
| Streaming connection | World detail arrives late, data warnings appear or streamed scenery degrades while local frame times remain reasonable. | Check network stability, online-data options and cache behaviour. | A PC component upgrade is generally not the answer. |
| Frame pacing | The FPS counter looks healthy, but motion judders because frame times fluctuate or conflict with the display refresh cycle. | Use one stable frame cap and configure V-Sync or variable refresh correctly. | Usually none; correct synchronisation and frame-time spikes first. |
Which flight simulator settings should I change first?
Change only the settings associated with the measured bottleneck rather than applying a Low preset that sacrifices unrelated image quality.
Settings for a main-thread or CPU limit
Start with terrain level of detail, object level of detail, autogen or scenery density, AI aircraft, airport vehicles and road traffic. The names vary by simulator, but these settings increase the number of objects and calculations the main thread must prepare.
Complex aircraft can also be the difference. Glass-cockpit displays, systems simulation and external traffic injectors may consume substantial CPU time, so compare the problem aircraft with a default one before blaming the entire PC. Older simulators such as FSX can remain main-thread limited even when paired with a much newer graphics card.
Settings for a GPU or VRAM limit
Resolution and render scaling provide the clearest GPU test. After that, lower volumetric clouds, shadows, reflections, ambient occlusion and demanding anti-aliasing options one at a time; our guide to identifying the settings that hit CPU, GPU and VRAM hardest explains the trade-offs without resorting to an indiscriminate preset.
Texture quality may have little effect on average FPS while enough VRAM is available, then cause abrupt hitching once detailed aircraft and airports exceed practical capacity. Monitoring software can report allocated memory rather than memory that is actively required, so confirm the diagnosis by lowering textures and repeating the same flight.
Upscaling can reduce GPU load, but it does not solve a main-thread limit. Frame generation can raise displayed FPS on supported hardware, yet it requires a reasonably stable base frame rate and cannot remove simulation stalls, scenery-loading pauses or control latency.
RAM, storage and streamed scenery
More RAM helps only when the system is genuinely short of memory and paging heavily. High RAM usage by itself is not proof of a shortage because Windows uses otherwise idle memory for caching.
An SSD improves loading and asset delivery compared with a hard disk, but moving from one healthy SSD to a faster model rarely cures a CPU or GPU frame-time limit. Both Microsoft Flight Simulator 2020 and Microsoft Flight Simulator 2024 can stream world data, so delayed scenery with healthy local frame times may be a connection, data-setting or cache problem rather than inadequate rendering hardware.
Why is my flight simulator choppy when FPS is high?
High average FPS can still look choppy when individual frames arrive unevenly or do not align with the monitor's refresh cycle.
After identifying the bottleneck, choose a frame cap the PC can sustain in the demanding test rather than allowing performance to swing constantly. With a variable-refresh display, keep the frame rate inside its supported range. On a fixed-refresh display, a stable rate that divides evenly into the refresh rate can look smoother than a higher but fluctuating number.
Use one primary limiter. Stacking the simulator's limiter, a graphics-driver cap and an overlay limiter can produce inconsistent pacing. Check the result in motion rather than relying solely on an FPS counter.
Regular spikes often indicate main-thread work, asset loading or an add-on rather than insufficient average performance. Frame generation may disguise the displayed rate between spikes, but it cannot generate its way through a stalled simulation thread.
Can add-ons be the real cause of poor performance?
Yes; one aircraft, airport, traffic injector or plug-in can cause CPU spikes, excessive VRAM use or pauses even when the base simulator runs well.
Test a default aircraft at a default airport first. If that is smooth, restore the affected aircraft, scenery, live weather, AI traffic and external utilities one category at a time. With a large add-on collection, disable half at a time to isolate the culprit faster than testing every package individually.
Compatibility problems can also appear after a simulator update, so a previously reliable package is not automatically cleared of suspicion. Our explanation of how to isolate aircraft, scenery and plug-in performance problems covers the clean-baseline process in more detail.
When is upgrading the PC the right answer?
Upgrade when controlled testing repeatedly identifies the same hardware limit and the settings required to avoid it make the simulator unacceptable for the way you fly.
- The problem appears in representative flights, not only with one unusually demanding or faulty add-on.
- Temperatures, power behaviour, background software and drivers have been checked.
- A clean simulator configuration shows the same limitation.
- A targeted setting change improves performance and therefore confirms the responsible component.
- The proposed replacement is a meaningful step rather than a minor change that will simply expose the next bottleneck.
Choose a CPU or platform upgrade for a persistent main-thread limit. Core count alone is not the deciding factor; flight simulators often depend heavily on the performance of the busiest simulation thread.
Choose a GPU upgrade when lowering resolution or render scaling gives a strong improvement, or when the card lacks enough VRAM for the aircraft, airports and resolution you normally use. Add RAM only for measured memory pressure, and prioritise an SSD when the simulator is still running from a hard disk.
Before buying anything, use our component-by-component upgrade checks for flight simulators to match the purchase to the proven bottleneck.
Should I upgrade one component or replace the whole PC?
Replace only the limiting component when the rest of the system can support it without severe compatibility or performance compromises.
A complete replacement becomes more sensible when a CPU upgrade also requires a new motherboard and memory, the power supply or case cannot support an appropriate graphics card, several components are below the required level, or the machine has poor cooling and limited expansion. Our upgrade-versus-new-PC decision guide covers those platform and compatibility checks.