DX11 or DX12 for Microsoft Flight Simulator 2020?
For most Microsoft Flight Simulator 2020 PC users, DX11 is the safer starting point because it usually gives steadier frame pacing and fewer rendering problems. Choose DX12 if it performs better on your own system or you need compatible NVIDIA DLSS Frame Generation, and keep it only after repeatable flights prove stable.
DX11 versus DX12: the quick decision
| Criterion | DX11 | DX12 |
|---|---|---|
| Best reason to use it | Predictable stability and frame pacing | Frame Generation or a measured performance improvement |
| Dedicated video memory | Usually more forgiving near the VRAM limit | Can hitch badly when VRAM is exhausted |
| CPU-limited performance | Reliable baseline | May reduce overhead on some systems, but not consistently |
| Image quality | Effectively the same at matching settings | Effectively the same at matching settings |
| Recommended default | Yes | Only where it provides a specific benefit |
The DirectX selector is a PC setting. Microsoft Flight Simulator 2020 on Xbox does not let the player switch between DX11 and DX12.
Does DX12 improve frame rates or graphics?
DX12 does not automatically improve image quality or performance in Microsoft Flight Simulator 2020. At identical graphics settings, the two APIs should look essentially the same; the practical difference is how the simulator, graphics driver and hardware distribute rendering work.
A system limited by the simulator's main thread may improve under DX12, remain unchanged or become less smooth. A GPU-limited system is unlikely to gain much merely by changing the API. Use the built-in Developer Mode FPS display to check whether the flight is labelled as limited by the main thread or GPU rather than guessing from average frame rate alone.
Before changing APIs, check our explanation of how MSFS graphics settings shift CPU and GPU load. Terrain Level of Detail, traffic, resolution and clouds often matter more than the DirectX version.
When is DX12 required for Frame Generation?
DX12 is required for Microsoft Flight Simulator 2020's in-sim NVIDIA DLSS Frame Generation on compatible RTX hardware. Do not confuse this with DLSS Super Resolution: DLSS upscaling can be available without Frame Generation, but the Frame Generation switch requires DX12.
Frame Generation increases the displayed frame rate by creating intermediate frames. It does not repair a poor underlying frame rate, and it can introduce latency or visual artefacts around cockpit displays and rapidly moving objects. Establish a smooth, playable base configuration before enabling it.
How should I test DX11 against DX12?
A controlled comparison on your own PC is more useful than another user's benchmark because aircraft, airport complexity, traffic, add-ons, resolution and graphics drivers can reverse the result.
- Fix the test scenario: use the same aircraft, airport, runway or parking position, camera view, weather preset and traffic settings. Avoid Live Weather while comparing because conditions can change between runs.
- Set the first API: select DX11 or DX12 in the PC graphics options, apply the change and restart the simulator fully. Leave every other graphics option unchanged.
- Allow the flight to settle: wait for scenery loading and shader activity to calm down, then observe several minutes of taxiing or flight. Record visible pauses, frame-time consistency and whether the simulator reports a main-thread or GPU limit.
- Repeat with the other API: restart after switching and fly the same sequence. Run each test more than once so a single loading pause does not decide the result.
- Choose smoothness over the peak: keep the API with consistent frame delivery and no crashes, even if the other produces a slightly higher frame-rate peak in an undemanding view.
Why does DX12 stutter or crash?
DX12 problems in MSFS 2020 most often come from VRAM pressure, graphics drivers, unstable GPU tuning, Frame Generation or software that hooks into the renderer. A crash under DX12 does not necessarily mean the simulator installation is damaged.
- If dedicated VRAM is close to full, lower Texture Resolution first and retest. Exceeding the available budget can cause severe pauses as data spills into shared system memory.
- Disable Frame Generation temporarily. This separates a DX12 problem from a Frame Generation problem.
- Return any GPU overclock or undervolt to its standard settings and test with a stable graphics driver.
- Disable graphics overlays and test with an empty Community folder. Ordinary aircraft and scenery should work under either API, but renderer-hooking utilities can behave differently.
- Expect temporary shader-related pauses after changing the API or graphics driver. Repeatedly deleting shader caches can make this initial stutter return.
If both APIs pause in the same places, follow our methodical checks for MSFS stutters and micro-pauses instead of continuing to swap DirectX versions.
The setting to keep
Keep DX11 when you do not need Frame Generation, have limited VRAM, experience unexplained crashes under DX12 or cannot measure a repeatable DX12 benefit. Keep DX12 when it enables a feature you use or produces demonstrably smoother performance without exhausting VRAM or reducing stability.
Retest after a major graphics-driver, simulator or hardware change, but do not switch APIs merely because another PC reports better numbers. In Microsoft Flight Simulator 2020, the best DirectX version is the one that remains smooth during your demanding flights, not the one with the highest frame rate in an empty cockpit test.