Fix screen tearing and horizontal lines in FSX with VSync, a stable frame cap, display-mode checks and targeted graphics troubleshooting.
To fix screen tearing in FSX or FSX: Steam Edition, run the simulator at your monitor’s native resolution, enable VSync for fsx.exe, and cap the frame rate at a level the PC can sustain. If the line remains fixed rather than moving during pans, troubleshoot the display connection or graphics hardware instead.
Is the horizontal line really screen tearing?
Screen tearing appears as a horizontal split that moves or changes position while you pan the view, turn the aircraft or scroll scenery across the screen.
| What you see | Likely cause | What to change |
|---|---|---|
| A moving split across the whole image | VSync is disabled or not being applied | Enable VSync and use a sustainable frame cap |
| Fine crawling lines on roofs, fences or the horizon | Aliasing, texture shimmer or excessive sharpening | Check anti-aliasing, filtering and graphics injectors |
| A fixed line visible on the desktop and in other programs | Monitor, cable, port or graphics hardware | Test another cable, port or display |
| Lines appearing only after installing an effect injector | Injector settings or the wrong DirectX hook | Disable the injector and test stock FSX |
How do I stop screen tearing in FSX?
The most reliable fix is to combine correct display settings, driver-level VSync and an FSX frame-rate target that the processor can hold consistently.
- Use the monitor’s native resolution. Set Windows to the intended refresh rate, then select the same native resolution in FSX. Avoid testing at a scaled or non-native full-screen resolution.
- Compare full-screen and windowed mode. Press
Alt+Enterand repeat the same outside-view pan. If tearing occurs only in full screen, the likely cause is the refresh or driver profile rather than scenery. Our guide to testing FSX windowed and full-screen modes covers the relevant display controls. - Enable VSync for FSX. In the graphics driver’s application profile, select the actual
fsx.exeused by your installation and set vertical synchronisation to On. Use the ordinary VSync mode for diagnosis; adaptive or fast modes can complicate the result. - Set a stable frame-rate target. On a 60 Hz display, try 30 FPS if FSX cannot maintain 60, or 60 if it can. Do not begin with Unlimited: FSX may produce a high average rate while delivering frames unevenly. If performance is too unstable for either target, use our FSX frame-rate and performance checks before adding more graphics tweaks.
- Remove competing graphics changes. Temporarily disable overlays, sharpening filters and post-processing injectors. Turn off DX10 Preview for one comparison if you use it. If the problem began with an injector, follow the ReShade configuration and removal checks for FSX.
- Restart FSX after each change. Driver profiles and full-screen settings may not take effect until the simulator is closed completely. Change one control at a time so you know which fix worked.
A mistake we see constantly is combining several frame limiters, driver overrides and old configuration tweaks at once. Start with one FSX frame cap and one application-specific VSync setting. The graphics driver’s OpenGL triple-buffering option does not solve tearing in DirectX-based FSX.
What if VSync does not work in FSX?
If the driver setting makes no difference, confirm that its profile points to the correct FSX executable and then try FSX’s configuration-level VSync controls.
Close the simulator and back up the active configuration file under %APPDATA%\Microsoft\. Boxed FSX and Steam Edition may use different FSX or FSX-SE folders, particularly when both are installed, so check which configuration file has the latest modified time rather than editing a similarly named copy in the installation directory.
Add these entries beneath the existing [GRAPHICS] section:
ForceFullScreenVSync=1ForceWindowedVSync=1
Do not create a second [GRAPHICS] heading. Save the file, leave it writable and restart FSX. Driver behaviour differs between Windows versions and graphics cards, so treat these entries as a fallback rather than stacking more synchronisation utilities on top.
If full-screen VSync still fails, test the Windows compatibility option that disables full-screen optimisations for fsx.exe. Keep that change only if it improves the result; on some systems the normal compatibility mode works better.
Why are horizontal lines still visible after enabling VSync?
Lines that remain with VSync enabled are often texture shimmer, sharpening artefacts or a physical display fault rather than screen tearing.
- Shimmer on scenery: enable FSX anti-aliasing, use anisotropic filtering and remove aggressive driver sharpening. Our display-resolution and anti-aliasing guidance explains how to distinguish shimmer from tearing.
- A line tied to one add-on: test the same location with default scenery and aircraft. If the artefact disappears, restore that add-on’s textures or configuration rather than changing global VSync.
- A fixed line outside FSX: replace or reseat the display cable, try another graphics output and return any GPU overclock to its standard settings.
- Corruption after a driver change: reset the FSX application profile to its defaults, recreate only the VSync setting and test again before changing the simulator configuration.
Should I use VSync, variable refresh or windowed mode?
Use ordinary VSync for a fixed-refresh monitor, variable refresh when FSX stays within the display’s supported range, and windowed mode as both a practical workaround and a diagnostic test.
With a variable-refresh display, cap FSX slightly below the monitor’s maximum refresh rate and verify that variable refresh actually engages with this older DirectX application. If it does not, fixed VSync with a 30 or 60 FPS target is usually more predictable. Windowed mode often removes tearing through Windows’ desktop compositor, although it may have different performance and input behaviour from full screen.