Which PC component should I upgrade first for flight simulation?

Upgrade the component that produces the longest frame time in your simulator. Choose a GPU when lowering resolution or render scale raises FPS; choose a CPU when traffic, avionics or scenery density is the limit. Add RAM only for measured memory pressure and paging, and use an SSD for loading or asset-streaming stalls.

This is general flight-simulator advice for Microsoft Flight Simulator, DCS World, X-Plane, FSX and Prepar3D; no component is universally the best first upgrade. Across our simulation community, the mistake we see constantly is buying a new graphics card before establishing whether the GPU is responsible for the poor performance.

How do I tell whether the CPU or GPU is limiting performance?

The reliable test is to change one class of workload at a time while watching CPU and GPU frame times in a repeatable flight. Frame time is more useful than average FPS because it reveals which side takes longer to produce each frame and exposes the spikes felt as stuttering.

1. Remove artificial limits. Temporarily disable VSync, frame-rate caps, frame generation and VR motion reprojection. A 30 or 60 FPS cap can make a capable GPU appear underused, while reprojection may hold VR at a fraction of the headset refresh rate.
2. Build a repeatable test. Use the same aircraft, airport, weather, traffic, cockpit view and flight position. Wait for the initial loading activity to settle; results recorded during spawning, shader preparation or scenery loading are not representative.
3. Record the baseline. Note CPU and GPU frame time, GPU utilisation, dedicated VRAM, physical and committed memory, storage activity, temperatures and clock speeds. Overall CPU utilisation is misleading because one critical simulator thread can be saturated while the processor reports moderate total use.
4. Reduce resolution or render scale. A substantial FPS or GPU frame-time improvement points to a graphics limit. Little change, accompanied by unused GPU capacity, normally indicates a CPU, frame-cap or simulator-engine limit.
5. Reduce CPU-heavy options separately. Lower AI or live traffic, terrain and object detail, scenery density, mirror rendering or cockpit-display refresh rates. If that helps while resolution changes do not, prioritise the CPU. Our setting-by-setting guide to CPU- and GPU-heavy options explains which controls make useful diagnostic tests.
6. Rule out false bottlenecks. Check for thermal throttling, background downloads, unstable overclocks, add-on scripts, network or scenery-streaming delays and nearly full storage. Our pre-upgrade performance troubleshooting process covers these causes before money is spent.

A simulator can change bottlenecks during one flight. A quiet cruise at high resolution may be GPU-limited, then become CPU-limited when a complex airliner approaches a detailed airport with traffic and working glass displays. The explanation of how flight-simulator workloads are divided between the CPU and GPU is useful when the result changes between scenarios.

What PC component should I upgrade first?

Upgrade the part supported by repeatable evidence, not the one showing the largest headline specification increase. Use this table as a decision guide.

Do not confuse allocated memory with memory genuinely required by the workload. Some simulators and drivers reserve substantial RAM or VRAM when space is available; allocation near the maximum does not, by itself, prove that capacity has been exhausted.

Different simulators have different upgrade priorities

Simulator engine design, aircraft complexity and the chosen scenario determine which component matters most. Minimum system requirements establish whether software should run, but they do not identify the part limiting a specific PC.

Microsoft Flight Simulator 2020 and 2024

Microsoft Flight Simulator often becomes CPU-limited around detailed airports, dense traffic and complex glass-cockpit aircraft. Terrain Level of Detail, Object Level of Detail, traffic and cockpit displays can increase main-thread load; high resolution, VR, render scaling, clouds and anti-aliasing place more pressure on the GPU.

Streaming or cache interruptions can resemble a slow SSD or CPU. Re-test with third-party add-ons disabled, a controlled weather preset and normal network conditions before replacing hardware.

DCS World

DCS World can be CPU-limited by large missions, AI units, scripts and complex multiplayer scenarios, while high-resolution displays and VR can demand considerable GPU performance and VRAM. RAM shortages tend to appear as long pauses, heavy paging, failed mission loads or instability rather than a small, consistent FPS reduction.

Test the mission type actually flown. A simple free-flight mission is not a useful hardware guide for a large campaign or multiplayer server, and a demanding mission should not be used to predict every DCS workload.

X-Plane, FSX and Prepar3D

X-Plane can expose a CPU limit through object density, traffic and processor-heavy plug-ins, while resolution, anti-aliasing, clouds and visual effects can expose the GPU. FSX and many older Prepar3D installations are strongly influenced by main-thread CPU performance, although newer rendering features, detailed scenery and high resolutions can still make the GPU relevant.

Ace Combat 8 PC performance

Ace Combat 8 should be assessed with its own PC build rather than by transferring DCS or Microsoft Flight Simulator recommendations. Its engine and mission workload differ, and a published requirements list only indicates broad compatibility; once the game is running, use the same resolution, frame-time and utilisation tests to determine whether a CPU or GPU upgrade would help.

Does VR limit the CPU or GPU?

VR can be limited by either component, although its high render resolution and strict frame-time target frequently expose the GPU first. The CPU must still run the simulation, prepare draw calls, update cockpit displays and support the VR runtime, so dense traffic or a complex DCS mission can remain CPU-limited inside a headset.

• Suspect the GPU when reducing headset render resolution or simulator render scale materially improves frame time.
• Suspect the CPU when lowering traffic, objects, mirrors or cockpit-display updates helps but reducing VR resolution does not.
• Check reprojection when FPS appears fixed at one-half or another fraction of the headset refresh rate. That is a timing mode, not automatically the maximum performance of the hardware.
• Use VR frame-time telemetry where available. Desktop FPS counters may not reveal missed headset frames or the separate CPU and GPU timing budgets.

A faster GPU cannot fix a main-thread limit, and a flagship CPU cannot compensate for a GPU that misses the headset's render deadline. Diagnose VR in the aircraft and mission actually used, at the intended headset resolution.

When should RAM or an SSD be the first upgrade?

RAM should come first only when memory pressure is measurable, while an SSD should come first when storage latency is causing loading or asset-delivery stalls. Neither upgrade normally cures a pure CPU or GPU frame-time limit.

Microsoft's published PC tiers for MSFS 2024 list 16 GB of RAM at the minimum tier, 32 GB at the recommended tier and 64 GB at the ideal tier. These are planning levels rather than guarantees: a PC with 32 GB and no paging will not gain substantial FPS merely from installing 64 GB, while complex add-ons, large scenery packages and background applications can make extra capacity useful.

Windows uses spare RAM for caching, so high utilisation alone is not proof of shortage. Look for committed memory approaching the commit limit, sustained hard faults, page-file activity and pauses that occur together. Faster RAM can modestly help a CPU-limited system, but capacity and stability take priority over advertised memory speed.

An SSD is a strong upgrade if the simulator still runs from a mechanical hard drive. It shortens loading and can reduce stalls caused by local scenery or texture access, but it seldom raises sustained FPS once the required assets are in memory. Leave free capacity for simulator updates, rolling caches, temporary files and add-ons.

What should the DCS pagefile be set to?

For DCS World, leave the Windows page file enabled and system-managed on an SSD with ample free space unless a qualified troubleshooting process requires a different configuration. There is no universal fixed DCS pagefile size that suits every RAM capacity, mission and collection of background applications.

The page file increases the system's commit limit; it does not turn an SSD into fast RAM. Disabling it can cause crashes or failed mission loads even when the physical-memory reading does not appear completely full. Conversely, making it extremely large may prevent an out-of-memory failure but will not remove stuttering if DCS is actively paging data between RAM and storage.

If heavy page-file use is repeatable in representative DCS missions, close unnecessary applications and inspect mission or add-on usage first. Add RAM when committed memory regularly approaches the limit and storage activity accompanies severe pauses. Keep enough free SSD space for Windows to manage the file rather than copying an arbitrary fixed value from another PC.

Should I upgrade to MSFS 2024 or upgrade my PC first?

Treat moving to MSFS 2024 and replacing PC hardware as separate decisions. MSFS 2024 is a separate simulator release rather than a performance patch for MSFS 2020; it launched on PC on 19 November 2024, and Sim Update 5 was released in April 2026.

• Choose the simulator upgrade for the MSFS 2024 features, aircraft and activities you want, after checking that essential peripherals and third-party add-ons are supported.
• Choose a hardware upgrade only when testing identifies a CPU, GPU, RAM or storage limit at the resolution and settings you intend to use.
• Prioritise RAM capacity when a 16 GB system is demonstrably paging in busy MSFS 2024 scenarios. A system already fitted with 32 GB should be measured before moving to 64 GB.
• Do not blame hardware immediately for pauses caused by streamed scenery, network conditions, cache behaviour or an incompatible package in the Community folder.

Performance in MSFS 2020 is useful context but not a guaranteed prediction for MSFS 2024. Re-test equivalent aircraft, airports, weather and traffic after the software change because the active bottleneck may move.

Compatibility checks before buying a PC upgrade

A proposed component must be compatible with the rest of the PC and large enough to deliver a meaningful improvement. Replacing one part is poor value when several supporting components must also change.

• CPU: verify motherboard socket and firmware support, cooler capacity and simulator-specific performance. Core count alone is not a useful ranking for flight simulation; main-thread performance and cache behaviour also matter.
• GPU: check power-supply capacity and connectors, case clearance, monitor resolution and CPU headroom. A faster card may add little FPS when the simulator is already main-thread limited.
• RAM: confirm motherboard capacity, supported memory generation and available slots. A matched kit is safer than mixing modules with uncertain timings, ranks or voltage requirements.
• SSD: verify interface support and make sure the simulator and relevant scenery libraries are actually moved to it. Installing an empty SSD does not accelerate files left on the old hard drive.
• Cooling and power: clear dust, repair failed fans and correct thermal or power throttling first. A faster component installed into the same cooling problem may simply throttle again.

If a useful CPU upgrade also requires a motherboard, memory and cooler—and the desired GPU would require a new power supply—the criteria for choosing between a single-part upgrade and a replacement PC can prevent money being sunk into an obsolete platform.

The practical rule: buy a GPU when lowering resolution clearly helps, buy a CPU or platform when traffic and scenery complexity control frame time, add RAM for demonstrated paging, and choose an SSD for storage-related stalls rather than low steady frame rates.