X-Plane 10 can run out of memory when the rendering settings are set too high or too many add-ons are running at once.  This article explains this problem and makes some recommendations about what to do about it.

X-Plane Runs Out of Virtual Memory

Because X-Plane is a 32-bit application, it can only use a certain amount of memory.  That limit varies by operating system:

  • Windows 32-bit: 3 GB.
  • Windows 64-bit: 4 GB.
  • Mac OS X: 3.5 GB.
  • Linux: 3 GB.

Because this is a virtual memory limit on each application, these limits apply no matter how much physical memory you have in your computer; even if you have 16 GB of RAM, these limits apply.  There are no operating system settings that raise these limits beyond what is listed.

Symptoms of Virtual Memory Exhaustion

When X-Plane runs out of virtual memory, you may see a message like this:

X-Plane is running very low on memory.
Scenery loading is now disabled.
Please turn down your settings and restart the sim as soon as possible.

This message appears when X-Plane is right on the edge of virtual memory.  At this point, scenery will stop loading and you should turn down your rendering settings and quit and restart the sim.  See below for suggestions on how to reduce memory usage.

You may also see this message:

X-Plane is totally out of memory.
Next time, turn down your rendering settings or remove add-ons to avoid this problem.
If you cannot restart X-Plane you may have to delete your preferences, in the Output folder.

This means that X-Plane is totally out of memory and cannot operate.  If you see this message when starting X-Plane up, it means your saved preferences are set too high for your computer.  If this happens, open the Output folder (in the X-Plane folder), the the Preferences folder inside Output, and delete the files called X-Plane.prf and X-Plane Screen Res.prf.  This will reset all rendering settings to their defaults but it will not reset your customized keyboard shortcuts.

The third symptom of memory exhaustion is a hard crash.  If X-Plane runs out of memory, sometimes the OpenGL driver can crash before X-Plane can display an error message.

Reducing X-Plane’s Virtual Memory Use

There are a few ways you can reduce the amount of virtual memory that X-Plane needs to operate.

The first thing you can do is remove add-ons.  Plugins, custom airplanes, and custom scenery can all increase the amount of virtual memory that X-Plane uses.  Try removing add-ons and see if the problem goes away.  Add-ons can also increase the amount of memory that X-Plane itself uses. You may have to mix and match add-ons depending on your activities.

The second thing you can do is turn down X-Plane’s settings.  Here are some settings that make a difference in virtual memory usage.

  • AI traffic.  More planes uses more memory, and more complex and higher detail planes use more memory.
  • Texture resolution: turn texture compression on – it saves a lot of memory.  Turn down texture res as needed.  In particular, do not run with extreme res and uncompressed textures.
  • Trees – turn down the forest density to save memory.
  • 4x SSAA – when in HDR mode, turn off 4x SSAA if you use a large monitor or a large window size.
  • If needed, turn down object density.


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