The following procedure will allow you to optimize X-Plane’s performance for your computer, regardless of the power of that computer or any limitations it may have. Before we begin, we will need to be able to tell how fast X-Plane is running on your computer. To do this, launch X-Plane and:
- Move your mouse to the top of the screen (causing the menu to appear) and click Settings, then Data Input & Output.
- Check the far right box next to frame rate item 0, in the upper left corner of the window). This will cause X-Plane to display the current frame rate in the upper left of the screen during flight.
- Close the Data Input & Output window (either with one of the Xs in the corners of the window or with the Enter key on the keyboard). You should now see how fast the simulation is running, in the freq/sec output on the far left. This is the current frame rate, given in frames per second (fps)
Note that the frame rate will change depending on what is happening in the simulation. It is not uncommon for a computer to output 50 fps while sitting on an empty runway, but drop down to, say, 30 fps when rendering lots of buildings, other aircraft, etc.
Refer to the following to determine the significance of this number.
- 19 fps is terrible and barely adequate to run the simulator.
- 25 to 35 fps is the ideal range. Higher frame rates indicate the computer isn’t rendering with as much detail as it could.
- 50 fps is very high and indicates that the system could probably draw more buildings, clouds, and other objects. Studies have shown that starting at about 50 frames per second, your subconscious mind forgets that you are looking at a simulator and begins thinking you are actually flying.
Increasing the Frame Rate
If the simulator’s frame rate isn’t as high you would like, you can raise it by following the instructions below. We recommend following these instructions in order, checking the frame rate after each major change until you find settings that give an acceptable frame rate.
Changing Texture Quality
If your graphics card has too little VRAM for the textures X-Plane is loading (a very real possibility in Version 10), you may see a huge drop in frame rate. To correct this, try the following.
- Move the mouse to the top of the window, making the menu bar appear, and click Settings, then click Rendering Options.
- The texture resolution drop-down menu determines how much video RAM (VRAM) the computer will use. If your graphics card has plenty of VRAM, you can set it as high as you want with no loss in frame rate, but as soon as the texture resolution requires more VRAM than the graphics card has, the simulator’s frame rate will plummet.
- To determine how much VRAM is being used at the current settings, look at the very bottom of this window. The last line reads “Total size of all loaded textures at current settings: xxx.xx meg.” While it is in some cases possible to load more textures than can be stored in VRAM without a performance hit (as not all textures will be used all the time), the size of the loaded textures should not be significantly greater than the VRAM on the system’s video card.
- Lower the texture resolution if the current settings require much more VRAM than your video card has.
After changing the texture resolution, X-Plane must be restarted for the change to take effect. We recommend putting the texture resolution on its lowest setting, exiting the sim, restarting it, and noting the frame rate. From there, raise the texture detail up one level and repeat until the frame rate decreases. This is the point at which all of the video card’s RAM is being used. Back the texture resolution off to one level lower than where the decrease was noted and restart X-Plane one more time.
If, after restarting X-Plane, your frame rate is still low, you may want to disable some of the newer features of the X-Plane renderer, such as HDR rendering and global shadows.
Disable HDR Rendering, Simplify Shadows, and Lower Water Reflections
The latest rendering features in X-Plane 10 (HDR rendering, global shadows, and water complex water reflection) can be very costly on older computers. HDR rendering is potentially quite GPU-intensive, and global shadows and water reflections are both CPU- and GPU-intensive. Therefore, if you are having issues with the frame rate, should be some of the first options to go.
Uncheck the HDR rendering option (located in the Special Effects portion of the window). Next, set the shadow detail located in the Stuff to Draw portion of the window) to either “overlay” or “3-D on aircraft.” Finally, set the “water reflection detail” to “none.” Restart X-Plane, and you should see a dramatic rise in frame rate. If, however, the frame rate is still unacceptable, you may need to change the resolution as well.
Changing the Resolution
The screen resolution refers to the number of pixels that X-Plane must fill. The lowest available (and default) resolution is 1024 x 768. Increasing the resolution will cause a drop in frame rate if your graphics card is not powerful enough.
When using X-Plane in windowed (i.e., not full-screen) mode, simply dragging the window size down will lower your resolution. When using X-Plane in full-screen mode, open the Rendering Options by moving the mouse to the top of the screen, clicking Settings, then clicking Rendering Options. Since the run full-screen at this resolution box must be checked for full-screen mode, you can use the drop-down menu to the right of that box to choose a lower resolution. Try 1024 x 768 first to see if lowering the resolution does indeed improve your frame rate. Note, however, that choosing a resolution different from the resolution set in your operating system may cause X-Plane to display a black border around the simulator.
Optimizing Other Rendering Options
A few more rendering options are very important in getting the best performance in X-Plane on your computer. Once again, to modify the rendering options, move your mouse to the top of the screen, click Settings, and click Rendering Options.
On most computers, the rendering options with the greatest impact on performance are the number of objects, number of roads, and number of cars, simply because these are CPU-limited rather than being GPU-limited. These settings have a huge impact on frame rate. Set them to none for the most speed, then restart X-Plane for the changes to take effect. Check the frame rate, bring both settings up one level, and repeat, restarting the simulator each time to see how performance is affected. Setting these options to higher levels will look much nicer but will negatively impact the X-Plane’s frame rate.
Another important factor for X-Plane’s performance is the world detail distance setting. This setting determines how far away from your aircraft the simulator’s 3-D objects will be rendered in high quality. Doubling the detail distance will cause X-Plane to draw four times as many objects. This is due to the fact that, from the aircraft’s point of view, the number of objects rendered will grow in all directions equally. You may want to change this from default to low if frame rate is at issue.
Higher values in the airport detail field will give, among other things, nice 3-D runway lights, center line lights, and runway edge lights instead of simple, bodiless spots of light. These effects contribute to a very authentic look for airports, but since these are only visible near the ground, you may find the default value an acceptable compromise; lowering this setting can improve performance significantly.
Tuning for Orthophoto Scenery
Orthophoto scenery comes in a few different forms:
- DSF base meshes and ENVs (an ENV always has a mesh)
- Overlay DSFs (with draped polygons).
If an orthophoto scenery package uses overlay DSFs, X-Plane will become limited by its ability to fill in screen pixels on all but the fastest cards, because X-Plane must draw the base mesh, then draw the orthophoto overlay over it.
- Turn down full-screen anti-aliasing.
- Decrease X-Plane’s window size.
- Turn down pixel shader settings.
All three of these consume the graphics card’s ability to fill in pixels; in particular combining these options can slow you down a lot. So at large resolutions, turn down anti-aliasing or pick simpler shader settings.
Modifying Cloud Rendering and Visibility
Another group of settings that can be modified for performance are the weather effects.
The number of “puffs” in each of X-Plane’s clouds can significantly affect performance. To get a boost in frame rate, first open the Rendering Options as described above. There, drag the number of cloud puffs slider down, perhaps to 10 percent.
A further increase in frame rate can be obtained by drawing only a few simple clouds, with relatively low visibility. To set this, do the following:
- Bring down the menu as above and click Environment, then Weather, as shown in the image above.
- Select the radio button labeled “set weather uniformly for the whole world,” located near the top of the screen.
- Using the three cloud drop-down menus (found in the upper left of the screen, and pictured in the image to the right) , set the cloud types to “clear” or “cumulus overcast” for max frame rate. For a good frame rate, set them to “thin cirrus” or “stratus.” “Cumulus scattered” or “cumulus broken” take a lot of computing power to display.
- Set the visibility (found on the left side of the screen) to about five miles or so. Higher visibility takes more computing power because the computer has to calculate what the world looks like for a much larger area.
Changing the Number of Other Aircraft
The final setting that really impacts the simulator’s frame rate is the number of other airplanes. Access this by moving the mouse to the top of the screen, clicking Aircraft, then selecting Aircraft and Situations. In the dialog box that appears, go to the Other Aircraft tab.
There, the number of aircraft setting (found in the upper left of the screen) should be set to one for maximum speed. This means X-Plane will only have to calculate physics on your aircraft, providing a significant speed increase on slower CPUs.
With that done, your performance should be optimized, and you’re ready to fly.