topic Re: Performance issues when using OpenGL Rendering in VRED 2025.3 with OpenXR in VRED Forum

Performance issues when using OpenGL Rendering in VRED 2025.3 with OpenXR

clemens_schlicker_audi — Thu, 03 Apr 2025 13:41:43 GMT

System information:

Nvidia RTX 6000 Ada x2 with Nvidia Driver 553.62, SLI (via PCI) activated
Varjo XR-4 HMD with Varjo Base 4.7.1.10 (and LPVR-CAD 4.9.1)
VRED 2025.3 with default new scene, default settings (no user-defined 3d content)
new HP Z6 G5 A Desktop-Workstations with Windows 10 (Version 10.0.19045 Build 19045)

Observation

View » Display » OpenXR HMD
Visualization » Raytracing » Off
- ~12 fps according to VRED statistics
- ~5-7 fps according to Varjo Base
- GPU Utilization ~26% (both GPUs)
- Video Memory used: 6117/49140 (both GPUs)
View » Display » OpenXR HMD
Visualization » Raytracing » GPU Raytracing
- ~48 fps according to VRED statistics
- ~25 fps according to Varjo Base
- GPU Utilization ~70% (both GPUs)
- Video Memory used: 16696/49140 (both GPUs)

As a comparison I opened VRED 2023.2 on the same pc with the same scene and default settings.

View » Display » Varjo HMD
Visualization » Raytracing » Off
- 75 fps according to VRED statistics
- 75 fps according to Varjo Base
- GPU Utilization 28% & 16%
- Video Memory used: 4302/49140 (both GPUs)
View » Display » Varjo HMD
Visualization » Raytracing » GPU Raytracing
- Not supported, doesn't work in the Varjo XR-4, so don't consider these values as valid
- ~25 fps according to VRED statistics
- ~25 fps according to Varjo Base
- GPU Utilization ~82% & 70%
- Video Memory used: 13760/49140 (both GPUs)

I know that I should enable the options in the following options in the VRED preferences (especially for larger scenes) :

"Render Window » Advanced Rendering » Clear GPU Memory"
"General Settings » Features » Optimization Mode » Optimize Memory Consumption"

Unfortunately, I can't achieve better results and I'm puzzled by the performance drop compared to the previous version.

Any recommendations regarding the system setup (e.g. Nvidia driver) or other settings?

Re: Performance issues when using OpenGL Rendering in VRED 2025.3 with OpenXR

Christian_Garimberti — Sat, 05 Apr 2025 15:19:34 GMT

Hi @clemens_schlicker_audi, maybe it is not your case, but i have many performance issues with my HP Z6 and Z8.

And it is related to usb connections. I never found a real solution, but it is very important to find the "better" configuration of attached devices.

In my case if i leave the usb and the mouse connected on the USB ports on the back, side by side with the XR-3 USB, i got very poor performance. I tried to connect the mouse and the keyboard on the front USB and it got better.

Maybe it is not your case, but i could also check this.

best

Chris

Re: Performance issues when using OpenGL Rendering in VRED 2025.3 with OpenXR

michael_nikelsky — Sun, 06 Apr 2025 16:38:15 GMT

There is sadly a performance issue when using OpenXR on multiple GPUs with the SteamVR backend in 2025.3. It looks like we are triggering an extremely slow path in the GPU driver due to change trying to work around some issues in OpenVR. Sadly the only workaround is to only use one GPU in OpenXR.

I am not sure though why you are comparing OpenXR with the native Varjo implementation, which is still available in 2025.3. Is there a reason for that?

Re: Performance issues when using OpenGL Rendering in VRED 2025.3 with OpenXR

clemens_schlicker_audi — Mon, 07 Apr 2025 06:47:47 GMT

Hi @michael_nikelsky , thanks for the confirmation of an observation that I’ve made on another computer. There I somehow forgot to activate SLI and as soon as I activated it, the performance got significantly worse. So it’s a general issue when using SLI and OpenXR (with SteamVR backend) in VRED 2025.3. Good to know!

You asked why I didn’t compare OpenXR to the native Varjo implementation [I assume that you missed a “not” in your sentence].

In VRED 2025.3, I get an error when trying to use Varjo HMD that states that the device wasn’t found. Consequently, I have to use OpenXR.

Should my question rather be: “Why can’t I use the Varjo XR-4 with the native Varjo HMD Display mode?”

Re: Performance issues when using OpenGL Rendering in VRED 2025.3 with OpenXR

clemens_schlicker_audi — Mon, 07 Apr 2025 10:02:39 GMT

#issue_1

OpenXR doesn't work with enabled SLI (see above)

#solution_1

Don't use OpenXR in this case and use Varjo HMD, if possible!

#issue_2

Can't use "View » Display » Varjo HMD" due to error "Failed to init open vr system with error Installation path could not be located (110)"

#solution_2

Install Steam VR despite not needing the software at all when using Varjo with the LPVR plugin.

With the installation folder on disk where VRED expects it, "Varjo HMD" can be activated.

Thanks @michael_nikelsky for the hint and the motivation to get "Varjo HMD" running in VRED again!

Thanks @Christian_Garimberti for the suggestion to try out other USB ports! Especially when dealing with high-bandwidth communication (like 20 Gbit/s), shared bandwidth among internal USB controllers can be an issue as bad as crosstalk between insufficiently shielded cables. In this case, I used the USB-C plug in the front for XR-4 and all rear ports for other devices.

I'm still wondering why Audodesk VRED requires me to have Steam VR installed despite not using it at all. Can that be implemented in another way? Is it really neccessary?

Re: Performance issues when using OpenGL Rendering in VRED 2025.3 with OpenXR

marc.arends — Mon, 07 Apr 2025 12:24:28 GMT

Hi @clemens_schlicker_audi,

the reason for the SteamVR requirement is simply that the native Varjo API currently does not provide access to controllers, at least this is my latest state of knowledge. Currently we require to initialize SteamVR to get all the controller information even for the XR-4 controllers that actually don't work with SteamVR tracking. Without this we also cannot find out, if controllers are even used.

Regards,

Marc

Re: Performance issues when using OpenGL Rendering in VRED 2025.3 with OpenXR

luqiang.han — Tue, 29 Apr 2025 00:54:56 GMT

Hello，Where is the path of SteamVR that VRED expects?

I have installed a standalone SteamVR in my computer, however, I faced the same problem of "Switching to HMD failed" when I use LPVR.

Re: Performance issues when using OpenGL Rendering in VRED 2025.3 with OpenXR

marc.arends — Tue, 29 Apr 2025 06:37:58 GMT

Hi @luqiang.han,

in general VRED doesn't expect any path as the OpenVR API handles that for the application, but you can check what OpenVR expects by opening the file in C:\Users\<your user name here>\AppData\Local\openvr\openvrpaths.vrpath which should include an entry where it expects the SteamVR runtime.

Regards,

Marc