Locked 90fps in AC Rally VR (UEVR) on my Crystal Light — DesktopXR's FOV culling is the trick

I found OpenXR Toolkit just crashes UEVR games. I wanted FOV cropping to improve performance.

Pimax Play technically has a FOV setting but it's just Narrow/Normal, and Narrow isn't well implemented — it chops the sides, which is the part you actually want in a sim racing. What I really wanted was to keep almost full width and trim the top/bottom, since you never look up at the sky from a cockpit anyway. It looks like you are looking through a helmet.

DesktopXR does exactly this. It is an OpenXR API layer, has per-side FOV culling control, and it doesn't fight with UEVR since it sits in the OpenXR pipeline instead of hooking the game.

Setup is dead simple:

1. Grab the .msi from the DesktopXR GitHub releases
2. Open %appdata%\DesktopXR\desktopxr.ini
3. Set your culling:

[FOV]
fov_enabled=1
fovcullleft=10
fovcullright=10
fovculltop=38
fovcullbottom=32

and save.

4. Restart the game (won't show in the Pimax home screen btw, only actual OpenXR apps)

If you don't want to edit the ini file, DesktopXR also comes with a configurator app that does the same thing through a UI, just remember to hit the save button.

Values are % culled per side. Yeah, 38/32 on top/bottom sounds brutal but through the Crystal Light lenses you barely notice it, and the GPU savings are huge.

My setup: Crystal Light, 9070 XT, 5700X3D. In-game settings all on low/very low except textures on ultra (textures are mostly VRAM, not GPU grunt, so ultra textures + low everything else is the sweet spot for VR clarity). I now have 90fps locked in VR.

I was down at about 45fps before using it, so I hope this helps someone that was in the same position as me!