Low FPS in VR: framerate too low or limited

This article is part of Virtual Reality.

Framerate is too low, what can I do?

• Increase the available amount of VRAM, as running out of VRAM will have a huge impact (see Windows Task Manager > Performance > GPU Memory Indicators). Here’s some ( tips to reduce VRAM use).
• Switch the Options > Display > Virtual Reality > Window View selector to Empty (fastest).
• Try reducing the graphics resolution in your headset’s software (typically located in Oculus/Meta/SteamVR/WMR/etc software settings page). Sometimes this is exposed as a 0-2x scale, or as a % percentage, with labels such as “supersampling”, or “pixels per display pixel”, etc. If your headset manufacturer doesn’t offer that option, open BeamNG > Options > Display > VR > VR resolution.
• Try reducing graphics detail ingame, in Options > Graphics (reflections are specially expensive).
• If you are using third party VR software, please try again with them disabled or uninstalled: they might be creating conflicts leading to low framerate.
• Use less demanding maps, less detailed vehicles and fewer vehicles.
• If you have disabled VR reprojection, enable it back to allow doubling your framerate when needed. If you don’t know what VR reprojection is, you don’t need to do anything.

Note: if the framerate is very consistently limited to certain value, this means the VR framerate limit is being hit. This FPS limit is intentional and normal for VR applications.

Framerate is limited, is that okay?

Short answer: Yes, framerate should be limited to certain value while in VR.

Long answer: Yes, when you use VR in any software, your framerate will be intentionally limited by design. You can think of this as a different kind of “V-Sync” that is necessary for VR to work. This FPS limit is imposed by the OpenXR runtime, and VR software like BeamNG.drive cannot (and should not) disable it.

The VR framerate limit depends on both your VR headset refresh rate, and on your minimum framerate (how low your worst fps is). The average framerate plays no role here.

• If your minimum framerate is greater than the refresh rate, then the limit will be the refresh rate:
  • For example, if you have a 90Hz headset and your minimum fps is consistently 95fps, then the limit will be 90fps.
• If your minimum framerate is lower than the refresh rate, but higher than half the refresh rate (*), then the limit will be that half:
  • For example, if you have a 90Hz headset and your minimum fps is consistently 85fps, then the limit will be 45fps. This can happen even if your average fps is much higher.
• If your minimum framerate is lower than half the refresh rate, the limit might get disabled:
  • For example, if you have a 90Hz headset and your minimum fps is consistently 40fps, then your framerate will probably stay unlimited at 40fps.

If you are curious as to what your framerate might be without this VR limit, you can press ctrl-f twice. The panel on the top-left of the window will display an “unmanaged” value. This is a very rough approximation, not 100% reliable, and tries to guess the framerate without fps limiting mechanisms like VR, V-Sync, FPS limiter, etc.

Or, if you are using the SteamVR runtime, you could also see the theoretical unmanaged frame period by enabling SteamVR > Settings > Advanced Settings > Developer > Show GPU Performance Graph in Headset. Frame period is the inverse of frame rate, e.g. 15ms of frame period means 1000/15ms = 66fps.

(*) When you are in the half-refresh-rate situation, VR reprojection will automatically kick in. Reprojection is what VR systems have used for the past decade to generate new frames when you cannot reach the minimum VR refresh rate. Reprojection generates new frames based on predictions, and will double the perceived framerate. For example, if you are getting 45fps and reprojection is enabled, then an additional 45 frames will be reprojected (generated), and the headset will receive 90fps total. These predicted frames may contain visual artifacts in some situations, since predictions can’t always be perfect. Reprojection is an important safety measure to avoid VR discomfort. If you disable it, you disable the ability to get that extra 2X framerate when it’s needed.