VR Performance Boost for Virtual Desktop

[slughead]

I recently switched from Meta Link to Virtual Desktop but haven't been entirely happy with the performance until now.

My PC is no slouch of a machine:

• Intel i9-13900k @ 5GHz
• Asus Nvidia 4090
• 64GB RAM @ XMP setting
• NVMe drive for Windows
• NVMe drive for DCS
• Windows 11 Pro
• Quest Pro headset

Meta Link and DCS Configuration:

• Meta Link x1.0 @ 72Hz.
• DCS PD 1.5
• Most, if not all, settings in DCS are maxed out (the configuration can be seen in the attached screenshots).
• DLSS enabled.

Performance Test:

I judged performance by flying the instant action, Persian Gulf, ready on-ramp mission with an F-16. It's not a scientific test, but it was a rough guide to see if a patch or driver update had broken something. The goal of the test is to remain out of ASW.

1. Take off, climb to 1200ft.
2. Turn right to the coast, maintaining speed at 450-500kts.
3. When the Burj Khalifa building is almost at my 3 o'clock, pull hard right towards it.
4. Then, I took another hard right again as I passed the building.
5. A well-performing system would make both turns and maintain 72 fps, staying out of ASW.

On the switch to VD, my settings were:

• Godlike resoluton @ 72Hz.
• DCS settings are the same except for PD.
• Any PD over 1.0 would cause a drop to ASW with the above test flight on the hard turns.

The image quality was identical/similar, but I was unhappy with the performance.

I realised that with the Meta Link, I had been using Oculus Tool Tray and had set the FOV to 90%, as some of us found that this gave a performance boost without affecting image quality. Effectively, it reduced the image size that was drawn but just about within the FOV, which was limited by the frame of the lenses. Any more than 90%, and you could start to see the edge of the image as a black rectangle.

When I turned off the 90% FOV in Meta Link, the performance was similar to Virtual Desktop.

So, to get the performance in VD that I had with Meta Link, I started making some adjustments using the OpenXR Toolkit.

OpenXR Toolkit has a FOV setting in the System tab. I set that to 90% but still had lower performance. Then, I looked at the render resolution in the dcs.log and found that it hadn't changed despite a reduced FOV.

To change this, I adjusted the display resolution, which was also in the System tab of OpenXR Toolkit. I lowered it to match the resolution created with Meta Link at a FOV of 90% and PD of 1.5. For me, that was 2904x3041.

With that change, the performance was back, and I am now fully converted to Virtual Desktop.

Yes, Virtual Desktop is more expensive because it requires a dedicated gaming router. You can get cheap ones and expensive ones. Either appears to work. Be sure to pick one from the list of tested routers. Yes, the bit rate is lower with VD. However, that's not an issue if you use one of the newer, more efficient encoders. I am using the HEVC 10-bit encoder, and I can't see a difference compared to H.264 @ 500 Mbps. Yes, Meta Link can run up to 960Mbps (not without distorting the audio via the link). Some say they notice a difference, but I don't.

For me, Virtual Desktop offers the peace of mind that Meta won't break DCS by changing their implementation of OpenXR on the Meta Link. It also allows you to see and interact with the Windows desktop, unlike Meta Link, where you have to peek under the headset to launch DCS. All in all, it is a better experience. To top it off, I am now wireless, which makes a huge difference. No more cable tethered to the PC! To maintain the charge of the headset, I use a power bank battery attached to a belt or in my pocket. Yes, there is a cable. I barely notice it.

In summary, if you want to get the boost you had with 90% FOV using Meta Link:

1. Find your DCS render resolution for your setup with Meta Link from the dcs.log file. If you are running DLSS, look for "DLSS successfully initialised". Mine is now: "DLSS successfully initialised, 1936x2032 -> 2904x3044".
2. Set the FOV to 90% in OpenXR Toolkit.
3. Adjust the "Display resolution (per eye)" in OpenXR ToolKit to match your old render resolution.
4. Enjoy the performance boost.

If you want a sharper image, you must sacrifice high CPU options such as shadows for higher resolution/increased PD.

 

[Phantom711]

vor 3 Stunden schrieb slughead:

It also allows you to see and interact with the Windows desktop, unlike Meta Link, where you have to peek under the headset to launch DCS.

I´ve heard/read that several times now... I mean WTF? If you start QuestLink and the environment changes into that grey "lobby", you simply click on the monitor symbol on the tray at the bottom and voila...you see your desktop. Now, don´t get that wrong. I tried VD as well and liked the better codecs. All I´m saying is, that being able to see the desktop is not an exclusive feature to VD that QuestLink wouldn´t have as well.

[slughead]

1 hour ago, Phantom711 said:

I´ve heard/read that several times now... I mean WTF? If you start QuestLink and the environment changes into that grey "lobby", you simply click on the monitor symbol on the tray at the bottom and voila...you see your desktop. Now, don´t get that wrong. I tried VD as well and liked the better codecs. All I´m saying is, that being able to see the desktop is not an exclusive feature to VD that QuestLink wouldn´t have as well.

But there is no hand-tracking / gesture control in the Quest PCVR lobby. So, if you don't use your Quest controllers like me, VD is the better experience. Anyway, this isn't about the Quest PCVR lobby but a performance boost for those who use Virtual Desktop.

Edited September 25, 2024 by slughead

[Phantom711]

Sorry, didn‘t want to derail your thread. I just found that part a bit misleading. And yes, you are right, the fact that one needs the controller for that is a bit annoying. Would be even better, if QuestLink was just defaulting to the desktop right away.

[sleighzy]

An alternative to the OpenXR Toolkit for this that some of us have been using is Quad-Views-Foveated instead. This works on both eye-tracked headsets, and non-eye-tracking headsets (I have a Quest 2) and also use VirtualDesktop. This is made by the same guy as the OpenXR Toolkit. Given that you're using an eye-tracked headset I would recommend you try this vs. OpenXR Toolkit as should give additional performance boost with the dynamic rendering. It provides the same FOV and focus multiplayer settings, and pushes some of this load back to your CPU...and as mentioned supports both dynamic and fixed foveated rendering.

See: https://github.com/mbucchia/Quad-Views-Foveated

In addition to this, see as how you're using an eye-tracked headset you may be able to use the companion app by TallyMouse for configuring this as well.

https://www.digitalcombatsimulator.com/en/files/3332882/

[slughead]

I have used QVFR. However, it can cause poor performance, especially when flying over cities with fast jets. Since DLSS was introduced, I no longer need to use QVFR. Now I have a clear image everywhere, whereas, with QVFR, there was always a split second where you looked that it would not be good until it caught up.

But again, this post isn't about QVFR. It's about reducing the FOV to gain performance, as we used to do with the Meta Link, but using Virtual Desktop. QVFR doesn't allow you to reduce the FOV image size; it only allows you to adjust the resolution of the periphery and central region of the image.

Here is the information about performance degradation with QVFR.

 

Edited September 27, 2024 by slughead

[Tomcat388th]

I tried your settings worked out fairly well. My setup is not as up to date as yours.  I used your pixel settings and fov at 90 but I had to use h264 instead of hevic 10 bit. It gave me problems DCS would hang up during mission load.  Not sure if it because I'm using a amd gpu or it latest drivers but 264 worked fine.  For me I found that if I used 90hz and locked it at 45 in the toolkit it ran really smooth even on 4YA Syria which for me is my test bed for MP.  I tried your settings with 72hz and ASW or what ever VD call it in auto my headset would loose tracking at times and the whole picture would move with my head like it was in 2d then it would kick back and track fine. Even with that glitch I was holding a constant 72fps in the 4YA server which I've never been able to do. That was with roughly 15 other players at that time.  When I changed the FOV you could see the outline as it changed had to restart DCS for the settings to take affect.  With your 4090 did it do the same thing?

J

[slughead]

9 hours ago, Tomcat388th said:

I tried your settings worked out fairly well. My setup is not as up to date as yours.  I used your pixel settings and fov at 90 but I had to use h264 instead of hevic 10 bit. It gave me problems DCS would hang up during mission load.  Not sure if it because I'm using a amd gpu or it latest drivers but 264 worked fine.  For me I found that if I used 90hz and locked it at 45 in the toolkit it ran really smooth even on 4YA Syria which for me is my test bed for MP.  I tried your settings with 72hz and ASW or what ever VD call it in auto my headset would loose tracking at times and the whole picture would move with my head like it was in 2d then it would kick back and track fine. Even with that glitch I was holding a constant 72fps in the 4YA server which I've never been able to do. That was with roughly 15 other players at that time.  When I changed the FOV you could see the outline as it changed had to restart DCS for the settings to take affect.  With your 4090 did it do the same thing?

J

Hey Tomcat! I have experienced the issues you describe, although they have nothing to do with changing the FOV or the render resolution. What you are experiencing is a high latency caused by either:

1. Your graphics card isn't powerful enough for the HEVC/H.265 encoder.
2. The HEVC encoder's bit rate is set too high. Let VD set it automatically. On the VD settings screen, hit the reset button.
3. You are using a shared WiFi router. Ideally, you would have a dedicated router for your headset only, with no other WiFi devices using it, so that your headset has the maximum bandwidth available.
4. Your router is not configured or capable of WiFi 6E.

H.264 is less demanding than HEVC/H.265, which explains why you have fewer issues with that encoder with your graphics card.

Additionally, locking half the frame rate doubles the frame time, giving your system more time to generate and send frames to the headset. If you solve your latency issues, you may not need to permanently run your headset in ASW/SSW.

Other things to check:

1. RAM set to XMP speed
2. Your CPU is not thermal throttling and thus slowing down
3. Your PCIe bus speed matches that of your graphics card - this can choke a system considerably

Edited September 28, 2024 by slughead

[Tomcat388th]

Another thing to add to the equation I recently upgraded from win10pro to win11 pro but that went fairly smooth.  I run an asus rt-ac68u the 5GHz is only used for DCS and 2.4GHz is used for the house. I also noticed that Godlike used to show my 6950xt now it listed with Ultra. Going to go back to my original settings and work back up one change at a time. Win10 it all ran fine. And one last question on the override resolution is there a list roughly showing what 1.1, 1.2 and 1/3 and so forth

Thank Again for the info

J

Edited September 28, 2024 by Tomcat388th

[slughead]

1 minute ago, Tomcat388th said:

Another thing to add to the equation I recently upgraded from win10pro to win11 pro but that went fairly smooth.  I run an asus rt-ac68u the 5GHz is only used for DCS and 2.4GHz is used for the house. I also noticed that Godlike used to show my 6950xt now it listed with Ultra. Going to go back to my original settings and work back up one change at a time. Win10 it all ran fine. And one last question on the override resolution is there a list showing roughly showing what 1.1, 1.2 and 1/3 and so forth

Thank Again for the info

J

Win11 is not the cause of your problem.

I'd appreciate it if you could start a new topic/thread about your connection/performance issues as this discussion is straying off topic of performance gain through FOV adjustment.

[Tomcat388th]

10 4 no problem  I backed it to Ultra and it's running fine at the moment. If it starts happening again I will start a new thread.

And again thank you 

J

[Qcumber]

On 9/28/2024 at 12:16 AM, Tomcat388th said:

I tried your settings worked out fairly well. My setup is not as up to date as yours.  I used your pixel settings and fov at 90 but I had to use h264 instead of hevic 10 bit. It gave me problems DCS would hang up during mission load.  Not sure if it because I'm using a amd gpu or it latest drivers but 264 worked fine.  For me I found that if I used 90hz and locked it at 45 in the toolkit it ran really smooth even on 4YA Syria which for me is my test bed for MP.  I tried your settings with 72hz and ASW or what ever VD call it in auto my headset would loose tracking at times and the whole picture would move with my head like it was in 2d then it would kick back and track fine. Even with that glitch I was holding a constant 72fps in the 4YA server which I've never been able to do. That was with roughly 15 other players at that time.  When I changed the FOV you could see the outline as it changed had to restart DCS for the settings to take affect.  With your 4090 did it do the same thing?

J

With your setup I would suggest using QVFR. Slughead's high end setup does not need it but you might see a noticeable improvement. 

[Tomcat388th]

I do use QVFR with my Pro

[dureiken]

Hi

 

thanks for your tip!

 

Is VR bitrate 60 enough for ultra ? thanks

[slughead]

56 minutes ago, dureiken said:

Hi

 

thanks for your tip!

 

Is VR bitrate 60 enough for ultra ? thanks

Plenty. This isn’t h.264 remember. HEVC is a far more efficient encoder.

[dureiken]

ok nice and is a 4070 Ti enough for HEVC ? thanks

[Qcumber]

2 minutes ago, dureiken said:

ok nice and is a 4070 Ti enough for HEVC ? thanks

I use a 4070 with hevc so I would say yes. 

[Kirk66]

Now that support for OpenXR Toolkit has been ended, and it's use discouraged, is there an alternative solution for reducing the FOV?

[slughead]

Discouraged? Can’t see why. It still works and as long as it does, carry on as usual. To answer your question… no, there is no other means to reduce the FOV in the context of this thread. It would be nice if some or all of the features of OpenXR Toolkit were integrated into VD.