OpenXR Toolkit Tuning Guide (updated 21/02/23)

[edmuss]

That's really odd, the quality/wide preset is my normal go to and that nets me about 1ms reduction with almost no visible loss (due to the reverbs blurred periphary).

Also currently testing the default recommended resolution of 2480 wide (for 8GB vram) with no upscaling and I'm getting 11.5-13ms frametimes, massively beating refresh at 16.6ms so super smooth

[Xupicor]

No effect for me.  No idea why.

Quote

testing the default recommended resolution of 2480 wide (for 8GB vram)

Can you elaborate? Are you using "override resolution" in the vr menu of OpenXR Toolkit? Or are you talking about NIS/FSR?

[mbucchia]

Have you checked this?

https://mbucchia.github.io/OpenXR-Toolkit/troubleshooting.html#checking-if-you-are-cpu-or-gpu-limited

[edmuss]

5 hours ago, Xupicor said:

No effect for me.  No idea why.

Can you elaborate? Are you using "override resolution" in the vr menu of OpenXR Toolkit? Or are you talking about NIS/FSR?

Resolution override in the system tab.

Openxr has a default recommended resolution based upon the amount of VRAM you have. The three frame buffers with MSAA x4 supplied should be no more than 10% of your available VRAM. This is what is set when you don't override it.

The G2 has a natural resolution of 3160 wide in software at 100%, because my 3070 only has 8gb it drops this down to 2480 wide. You can see what is recommended for your GPU on the second tab of the openxr XR tools desktop app.

Trying it out last night it vs FSR 150% (target resolution of 2160ish) it is actually as fast but looks better because there's less additional shimmering.

[Xupicor]

So, that's in the in-vr menu resolution override. OK, using that and your resolution value I can see performance gains - though the image quality is affected (as expected).  For the recommended value you mean OpenXR Tools for WMR -> "recommendedImageRect? Mine shows 3152x3088 which is indeed the default value in the in-vr menu.

Alright, I can work with this info. Thank you.

edit: @mbucchia thanks for the link. I have a question about this part:

Quote

When the value of app GPU is greater than the value of app CPU, you are limited by your GPU, and you may use features such as Upscaling or Foveated Rendering to relieve your GPU. If you are not GPU limited, then these features will not help to gain performance. Instead, you may alter other settings of your application, such as details settings, and increase them until you become GPU limited, and can enable the performance-enhancing features previously mentioned.

 

Is that the other way around? In a multiplayer training server with some things going on but relatively empty, I get around 45fps on the ground, app CPU is around 12500-13000, app GPU is about 16500. So I'm supposedly GPU bound according to the site, but FFR doesn't do anything for me. Even if I set it to Cull/Cull/Cull then the effect on framerate is negligible.

Edited July 26, 2022 by Xupicor

[mbucchia]

9 hours ago, Xupicor said:

So, that's in the in-vr menu resolution override. OK, using that and your resolution value I can see performance gains - though the image quality is affected (as expected).  For the recommended value you mean OpenXR Tools for WMR -> "recommendedImageRect? Mine shows 3152x3088 which is indeed the default value in the in-vr menu.

Alright, I can work with this info. Thank you.

edit: @mbucchia thanks for the link. I have a question about this part:

Is that the other way around? In a multiplayer training server with some things going on but relatively empty, I get around 45fps on the ground, app CPU is around 12500-13000, app GPU is about 16500. So I'm supposedly GPU bound according to the site, but FFR doesn't do anything for me. Even if I set it to Cull/Cull/Cull then the effect on framerate is negligible.

 

There are many potential bottlenecks in the GPU pipeline, and FFR (using VRS) is only helping at the Pixel Shader stage. So you bottleneck is likely somewhere else and FFR does not help with it.

[5ephir0th]

18 hours ago, Xupicor said:

So, that's in the in-vr menu resolution override. OK, using that and your resolution value I can see performance gains - though the image quality is affected (as expected).  For the recommended value you mean OpenXR Tools for WMR -> "recommendedImageRect? Mine shows 3152x3088 which is indeed the default value in the in-vr menu.

Alright, I can work with this info. Thank you.

edit: @mbucchia thanks for the link. I have a question about this part:

Is that the other way around? In a multiplayer training server with some things going on but relatively empty, I get around 45fps on the ground, app CPU is around 12500-13000, app GPU is about 16500. So I'm supposedly GPU bound according to the site, but FFR doesn't do anything for me. Even if I set it to Cull/Cull/Cull then the effect on framerate is negligible.

 

I see a better frametime when using FFR on my 3080ti, around 1-1.5 ms with custom settings, more if i use cull on the outer ring

[Burt]

Good Morning,

well I have OXR and my G2 running about best it can get so do you recommend disabling the toolkit. I’m not much of a tweaker and I think it’s as good as it’s going to get as of now. 

[edmuss]

I would utilise the toolkit, mainly because it allows you to tweak colours/levels/saturation/vibrance etc. in addition to providing FFR (if you fancy and extra 0.5-2 ms gain in performance).  Of course if you aren't using any of the functionality of it then you may as well disable it

[Burt]

18 minutes ago, edmuss said:

I would utilise the toolkit, mainly because it allows you to tweak colours/levels/saturation/vibrance etc. in addition to providing FFR (if you fancy and extra 0.5-2 ms gain in performance).  Of course if you aren't using any of the functionality of it then you may as well disable it

" tweak colours/levels/saturation/vibrance etc. " Okay I haven't did none that yet so I'll check that out today. I guess it doesn't hurt to just keep it enabled. 

Much Thanks 

[Digitalvole]

Bit of a moan about OpenXR incoming, so please forgive me, it won’t happen again.

Im going to try going back to SVR as I find OpenXR is blurry and the motion smoothing isn’t great even at 45fps.

Probably great for those struggling to maintain 45fps, but I seem to be pretty solidly at 45fps so due to the (imo) substandard motion smoothing solution it’s a downgrade in visual clarity for no real upside that I can see.

I would be very interested to hear from those with 3090s why they choose to use OpenXR as perhaps I’m missing something?

Edited August 1, 2022 by Digitalvole

[edmuss]

Reprojection in DCS with openxr is blurry and substandard in comparison to steamvr, it's a terrible shame that it's not been straightened out yet!

Have you tried turning reprojection off? If you can pull 55-60 fps @90Hz then it's pretty damn smooth (head rotations are synced but translations aren't - as most head movement is rotational I find it a moot point) but you get zero artifacts and no blurriness.  Admittedly this works better for slower movements like helos, fast movers low down can be uncomfortable if you're looking sideways 500 foot off the ground - I'd argue that you should be facing forwards in that situation!

I think in simplified terms, the way the openxr render handles vsync is that if you haven't achieved refresh rate it will hold the frame from being sent to the headset until the half refresh rate time, essentially if you're not achieving 90fps it will give you 45fps instead and simply wait so that it can sync the frame up with the headset position.  I understand that this is in opposition of how steamvr handles vsync and it just throws the frames out to the headset as soon as they're generated - this is why openxr appears much smoother at lower framerates (without reprojection) than steamvr.  Note that whilst the render is being displayed at 45Hz it will show a higher fps counter, I think this is because the actual number is averaged out based on the amount of time the renderer is waiting for the 45Hz vsync.

Alternatively if you can stomach 60Hz flicker and can keep above 60fps at all times then you will have perfectly synced image with no artifacts or blurring/ghosting.  However, as per the above paragraph, if you miss the 60Hz refresh target then it waits for the 30Hz (half refresh) and it gets really quite uncomfortable.  50fps on 90Hz is far nicer than 50fps on 60Hz.

If I can guarantee that I'll keep over 60fps (<16ms frametimes) then I'll happily the G2 run at 60Hz, on Foothold Caucasus for example it's been dropping to just below 60 for extended periods and as such it's far more comfortable at 90Hz; I can keep it above 60fps if I nail the resolution right down to 2400ish (and/or enable FSR) but both come at a significant loss of clarity.  Essentially as long as my minimum framerate is >45 (<22ms frametime) then I'm good to go, in fact I've put the G2 resolution back up to 100% because I don't need to mollycoddle the 3070 to get the last 10fps out to keep it above 60 - less shimmering, more clarity and 55fps is fine :)

[Digitalvole]

2 hours ago, edmuss said:

Reprojection in DCS with openxr is blurry and substandard in comparison to steamvr, it's a terrible shame that it's not been straightened out yet!

Have you tried turning reprojection off? If you can pull 55-60 fps @90Hz then it's pretty damn smooth (head rotations are synced but translations aren't - as most head movement is rotational I find it a moot point) but you get zero artifacts and no blurriness.  Admittedly this works better for slower movements like helos, fast movers low down can be uncomfortable if you're looking sideways 500 foot off the ground - I'd argue that you should be facing forwards in that situation!

I think in simplified terms, the way the openxr render handles vsync is that if you haven't achieved refresh rate it will hold the frame from being sent to the headset until the half refresh rate time, essentially if you're not achieving 90fps it will give you 45fps instead and simply wait so that it can sync the frame up with the headset position.  I understand that this is in opposition of how steamvr handles vsync and it just throws the frames out to the headset as soon as they're generated - this is why openxr appears much smoother at lower framerates (without reprojection) than steamvr.  Note that whilst the render is being displayed at 45Hz it will show a higher fps counter, I think this is because the actual number is averaged out based on the amount of time the renderer is waiting for the 45Hz vsync.

Alternatively if you can stomach 60Hz flicker and can keep above 60fps at all times then you will have perfectly synced image with no artifacts or blurring/ghosting.  However, as per the above paragraph, if you miss the 60Hz refresh target then it waits for the 30Hz (half refresh) and it gets really quite uncomfortable.  50fps on 90Hz is far nicer than 50fps on 60Hz.

If I can guarantee that I'll keep over 60fps (<16ms frametimes) then I'll happily the G2 run at 60Hz, on Foothold Caucasus for example it's been dropping to just below 60 for extended periods and as such it's far more comfortable at 90Hz; I can keep it above 60fps if I nail the resolution right down to 2400ish (and/or enable FSR) but both come at a significant loss of clarity.  Essentially as long as my minimum framerate is >45 (<22ms frametime) then I'm good to go, in fact I've put the G2 resolution back up to 100% because I don't need to mollycoddle the 3070 to get the last 10fps out to keep it above 60 - less shimmering, more clarity and 55fps is fine :)

Edmuss you must have a big brain! Thanks for the thorough explanation, I think I understood most of it. My brain isn’t so big.

I just don’t think no motion smoothing is an option if playing mp or Liberation, not yet at least. It’s fine though, I was happy with how I had things with SVR (I wasn’t at first but they must have released an update that really helped). 

I honestly couldn’t believe my eyes when I first tried OpenXR, then I turned on motion smoothing…

So there is hope. If they can sort that and we can have the best of both worlds they can help themselves to one of my kidneys! 

In the mean time I’ll stick with SVR, which isn’t something I thought I’d have ever said when I first tried it.

 

[edmuss]

Give it a try, you may be suprised, after so long relying on repojection as a crutch I was very leary of not using it when I switched to openxr

If your framerate is over >50fps in liberation then you should be laughing, also note that in steamvr, as soon as you're below 50ish fps the reprojection turns itself off anyway.

Before open composite / openxr was introduced for DCS I was forced to run in 60Hz mode, reprojecting down to 30fps simply because I couldn't hold enough performance overhead to keep steamvr reprojection enabled at 90Hz.

[Digitalvole]

I’ll give it a shot tonight, I had no idea SVR turns off reprojection if you go below 50fps. That seems daft to me (daft of them to make it like that) considering every frame counts in VR. 

[edmuss]

Reprojection works by guessing where the headset is going to be relative to the last couple of frames, generates a synthetic frame and inserts it in between the other frames to make it feel like you're achieving refresh rate; the guessed frames are why you get reprojection artifacts and distortion.  I think it's proven much harder to get right with openxr because of how the render times the frames being pushed to the headset in relation to the headset position - I'm not intimately familiar with the whole ins and outs but it's not an easy fix to get it as good as steamvr.

There is a computational overhead associated with calculating these synthetic frames which needs to be factored in to the equation as to whether or not you've achieved the refresh rate target you're aiming for (1/2 for steamvr - 1/2, 1/3, 1/4 for openxr).  For steamvr I roughly equated it as needing 55% of the refresh rate in order to keep reprojection enabled - it's not exactly 50fps.

With the openxr toolkit, because it can reproject at the lower fraction brackets of the refresh rate it means that if you drop below the threshold for 45Hz reprojection it will drop down to 30Hz (1/3) and then in turn down to 22Hz (1/4) before finally disabling; obviously the further from refresh you get you need to have more synthetic frames generated which introduces more artifacts.

Roughly with steamvr reprojection:-

>90fps = smooth and clear
<90fps but >50fps = smooth but with some artifacts
<50fps = janky but with no artifacts

Roughly with openxr reprojection:-

>90fps = smooth and clear
<90fps but >50fps = smooth but with some artifacts
<50fps but >33fps = smooth but with slightly more artifacts
<33fps but >22fps = smooth but with far more artifacts
<22fps = super janky but with no artifacts

The figures are obviously only nominal but having that safety net of the 30Hz bracket means that unless you're watching the frametimes/counters you'll likely not even notice that it's running at 1/3 of the speed it looks like.

If for example your CPU is stopping your GPU from achieving the reprojection fraction brackets then no amount of reprojection is going to help you

[Digitalvole]

5 hours ago, edmuss said:

Give it a try, you may be suprised, after so long relying on repojection as a crutch I was very leary of not using it when I switched to openxr

If your framerate is over >50fps in liberation then you should be laughing, also note that in steamvr, as soon as you're below 50ish fps the reprojection turns itself off anyway.

Before open composite / openxr was introduced for DCS I was forced to run in 60Hz mode, reprojecting down to 30fps simply because I couldn't hold enough performance overhead to keep steamvr reprojection enabled at 90Hz.

I’m reporting back after trying these things.

Basically It’s painfully close to being great but just not quite there. Im getting between 70-80fps once airborne and it’s all good till I look to the side, as you said, which is a pity but oh well. 

Also tried 60hz and good god no! Haha.

I reckon with a 4090 all may be well, but as always seems the way with DCS VR, perfection is still just out of reach.

Thank you again for all your help and advice

[edmuss]

Yeah 60 isn't for everyone.

You're very close, have you tweaked resolution and played with FFR and upscaling?

It's difficult with DCS because to keep the CPU times below 90Hz is very difficult with any significant load.

[Digitalvole]

19 minutes ago, edmuss said:

It's difficult with DCS because to keep the CPU times below 90Hz is very difficult with any significant load.

Exactly, I’ve hunted for 90fps in the past and decided it’s not going to happen with todays hardware.

If you can get the gfx to a point where you can keep GPU frame times below 10ms not only does the game no longer look “acceptable” if it’s cloudy or your flying low, as soon as you get in a busy mission your cpu will be above 10ms and render the whole exercise pointless.

I’ll be keeping a close eye on OpenXR as it seems very close to being the best. But in the mean time I’m going back to my old setup, which to be fair I was pretty happy with. 

[edmuss]

I don't think you're wrong, there's too much CPU dependency to keep the GPU running at full refresh rate. I that bigger GPUs at those point are just going to allow for higher settings but no more performance.

edit: as a test I reverted back to steamvr again, like for like settings, lost about 5-10 fps, a bunch of clarity and GPU frametimes were no where near as stable. 

A10C easy instant action - steamvr 50-60 fps with frametimes jumping quite violently from 16 to 18 - open composite 60-70 fps with stable frametimes from 14-16.

Edited August 1, 2022 by edmuss

[dooom]

what does it mean if it says "Target missed" below my OXRTK FPS counter?

[dooom]

Ok generally I am finding things smooth with the following:

AMD Chill off

OXRTK No upscale / MR "ON" FPS locked at 45.  (I try unlocked and the FPS plummet into the teens and I feel like it gets stuttery.

OXRDT - 90% custom resolution (can't really see a difference but i *think* its giving me enough fps to stay above 45

DCS MSAA x2, Textures HIGH, Terrain Textures on LOW.  Clouds standard, Vis MEDIUM, Aniso 16X

Is there any real reason to use upscale? Is there a way to balance the upscale against the 90% Custom resolution i have set in OXRDT?

 

I feel like a juggler.

[edmuss]

I'm not too sure what the target missed means, it might be a dropped frame? Not seen it myself.

edit: target frame missed might be because you've locked reprojection to 45hz but you're not achieving it.

If you turn on the openxr tools performance overlay, that will tell you appcpu and appgpu frametimes, these are essentially the time taken by your CPU and GPU to render the image.

11ms is 90fps, 16ms is 60fps, 22ms is 45fps (1000/frametime= fps)

This will give you a judge of what fps your achieving when MR is locking the fps to 45 (fps counters can't record the fps when reprojection is active but the frametimes will give you an idea).

If you have smooth image and adequate performance to keep reprojection running then there's no need to upscale it's purely there for performance reasons.

If you have 13ms frametimes for example you have loads of headroom to increase settings

Edited August 3, 2022 by edmuss

[dooom]

Ok - so how much performance can really be gained from using the upscaler?  If I'm struggling to keep my 45 fps low over high dense trees or buildings/units.  Should i be dropping the OXRDT custom resolution down more or using OXRTK upscaler?  And how much for the upscaler?  Do i just try like 90 or 110% and go from there to re-check if i'm getting to the 45 target?  I'm trying to wrap my head around how powerful the upscaling is for performance gains.

Thanks for suffering all my questions.  Hopefully others are learning as well

 

[dooom]

OK - i *think* things are dialed in as best they can be.

with MR Locked to 45, I am getting around 45% CPU headroom and about 10 ms most of the time high and low altitudes.

I really wish i could edit the OXRTK settings out of game.