Valve Index - OpenVR vs OpenXR

[Hartsblade]

I'm not sure if I'm the only one still running an Valve Index or not, but in light of the current patch I though I would share my results of running OpenXR instead of OpenVR.

I set up 2 separate Shortcuts, one with the the command line edit --force_enable_VR --force_OpenXR and one with the default route running no arguments (the OpenVR start up).  After launching and flying for a bit noting performance I shut down and checked the Log to verify which API was launched.

I like to do my "testing" using the Spitfire on the Channel Map - Instant Action/Free Flight.  One of the challenges of this map is flying low level over populated areas, there is a huge performance hit vs flying at altitude or flying over open water.  I took my readings from the same location for high Altitude/open water and flew low over the same section of city.  Multiple passes were run and compared.  I will report the averages.

Steam and DCS are below and Hardware is in my Siganture.

OpenVR Launch

High Altitude/Open Water
FPS:  60+ fps
GPU Frame Time:  12.1 ms
CPU Frame Time:  5.2 ms

Lower over city/populated area
FPS:  57 - 60 fps
GPU Frame Time:  16.2 ms
CPU Frame Time:  12.1 ms

OpenXR Launch

High Altitude/Open Water
FPS:  60+ fps
GPU Frame Time:  12.7 ms
CPU Frame Time:  5.7 ms

Lower over city/populated area
FPS: 40-45 fps
GPU Frame Time:  19.1 ms
CPU Frame Time:  12.7 ms

With my current Settings I can keep a constant 60fps (or better) both at altitude and down low over populated areas using the default start, which launches into OpenVR.

With the Edited Start forcing OpenXR I still get a constant 60fps at altitude, but when I run down low over the buildings the FPS drops to 40 (or less).

SteamVR Settings

DCS Grraphics Settings

Edited January 28, 2023 by Hartsblade
Typo

[Supmua]

The CPU frametime numbers mirror my findings with the Varjo Aero, slight increase with OpenXR.  I got similar GPU frametime numbers with both APIs though.  This is just initial observation, reproducibility remains to be seen.

Edited January 28, 2023 by Supmua

[RedeyeStorm]

Thanks for the report. I am also using Index and I always wondered if it would serve a purpose. Now I know to leave it alone.