Settings for slower graphics cards

Some of us don't have the luxury of using the highest-end graphics cards. Fortunately, FlightGear can still render you enjoyment in the skies with a few strategic settings optimizations. The optimal settings may differ depending on your particular computer's hardware setup, so these are just suggestions from which you can experiment.

Although the hardware may be more or less fixed, a few tweaks can make the difference from 2 fps -> 10+ or even as high as 30 fps. Consider these adjustments to see if you can achieve high fps even without disabling FlightGear features.

Operating System

• Background programs: Check that your operating system is not cluttered by unnecessary programs running in the background. Have as little programs running as possible.
• Graphics card drivers: Ensure that the manufacturer's graphics card drivers are installed. For example, Windows may automatically install a generic graphics card driver that works fine for most applications but which does not offer OpenGL support. You may be able to download and install drivers specific to your card from the manufacturer's site. See Troubleshooting problems#Slow Framerate with OpenGL Card or About graphic drivers for additional information on drivers.
• Maximize power performance settings: If you're running a laptop, chances are your system defaults to a power-saving mode, even with the laptop plugged in. Adjust these settings to maximal power while running FlightGear.
• Disable Optimus/Hybrid Graphics: Most notebooks that run Windows 7 have the so called Optimus Technology (NVidia) or Hybrid Graphics technology (ATI) onboard. This is meant to increase battery life, by automatically switching of the powerfull graphics card when it's not needed. However, FlightGear needs it all the time, even if Optimus says it doesn't! This miscommunication results in low framerates (because your computer will run Flightgear on the weak onboard processor). See Howto: Improve framerates#Optimus Technology for further reference and instructions on how to disable it.
• Graphics improvements: Disable Anti-Aliasing and Anisotropic Filtering or at least set them to their lowest settings. Decreasing the setting for Mip-Mapping to its lowest setting can also help.

FlightGear

These settings are specific to FlightGear. Try to disable them one by one to see their effect and determine their impact on FlightGear performance.

General Considerations

• Balancing: Find a good balance between looks and performance. Chances are you can leave the odd visual feature enabled without sacrificing too much performance.
• Time of day: Changing from nighttime to daytime flying is not only easier on the piloting, but also easier on the graphic requirement. Check the "Time of day" box and select a daytime setting.
• Location: KSFO is a wonderful airport but also known for a high-volume of traffic, which can slow performance. Try another airport if you encounter performance issues.
• Rural flying: While framerate may initially be as slow as 5 fps during takeoff, they may jump 5x or more after flying out to less-populated areas.
• Weather: Fly in clear skies. Clouds always incur a more or less pronounced performance hit.
• Choice of aircraft: Certain aircraft have lower resource requirements. Here is a list of tested aircraft that are known to offer decent fps, especially over non-populated areas. Please add additional aircraft that you have found to work well on lower-powered computers.
  • UFO: Very high performance (30+ fps) with minimal resources.
  • Boeing Stearman: Decent performance (10+ fps).
  • Cessna Citation-X: Decent performance (10+ fps).
  • F-4E (David Culp's hanger): Decent performance (10+ fps).
  • F-5E: Good performance (up to 30 fps with shaders turned off).

FGRun

These settings are known to improve performance if disabled:

• Enhanced runway lighting
• Random trees
• Random objects

In "Advanced -> Rendering":

• Uncheck any remaining features
• Shading - Set to "flat"
• Fog - set to "nicest" or "disabled"

XML configuration files

See FlightGear configuration via XML for information on configuring FG with XML files.

Preferences.xml:

• Make sure that <rembrandt> is set to "false".
• Try to enable <multithreading-mode> by cut&paste-ing the "<--" in front of "Uncomment". If your framerate is lower with this setting enabled, disable it again.

Autosave.xml:

• If you can't live without random trees or houses, you can fine-tune their respective densities with the values storen in the "<vegetation-density>" and "<building-density>" elements.

In-flight settings

Some additional features can only be readily adjusted after boarding the aircraft. Use the "Show frame rate" option (in View > Display Options) to track frame rates in the lower right corner of the screen to see in real-time how your optimizations are speeding your rendering.

In "View -> Rendering Options":

Shaders:

• FlightGear 2.4: Uncheck the "Material Shaders" box.
• FlightGear 2.6+:
  • Move the "Shader effects" bar as far as possible to the "Performance" side or
  • Click "Custom" and disable shaders one by one to see which one affects performance the most.

3D Clouds: One of the worst offenders in terms of performance impact. Disable them.

Random Buildings: Disable them if not deemed important or leave them enabled, but lower their density in the Autosave.xml (see above).

Random Trees: Disable or enable and adjust with the slider. Fine-tune in the Autosave.xml

Point Sprites: You'll need to restart FlightGear if you are unclecking this.

Random Objects: Usually not that demanding. Disable them as a last ditch effort.

In "AI -> AI Traffic"

Enable AI Traffic: Uncheck to enable "I am legend" mode.

Further Troubleshooting

System crashes: System Crashes

FlightGear crashes: Howto:Debugging FlightGear Crashes

Black textures on aircraft: Howto:Improve framerates#Texture compression

See also

Problematic Video Cards

Howto:Improve framerates