Quest 2 cuts framerate in half automatically when DCS loads, doesn't happen in other games.

[Granny]

I've been troubleshooting some issue in DCS on my Quest 2 and I think I may be on to something, but I don't know what to do about it.  I have notice that the DCS FPS counter shows I am getting FPS equal to half of the refresh rate of the Quest 2 headset.  I.e if set my Q2 at 120hz refresh rate I get a solid 60FPS on the counter.  I have heard that's the result of the headset effectively being 2 displays, one for each eye, thus 120/2 = 60.  I think that information is incorrect.  I recently discovered the Oculus Debug Tool and its performance Hud did a little investigating.  

This is what I see, before I load DCS, FPS is green and maxed out,  overhead is green and near 100%,  very few dropped frames.   As soon as the DCS load screen pops up (not even at the menu yet)  FPS instantly drops by half, and the dropped frame counter begins to sky rocker, yet my overhead remains green and near 100%. It stays the way until I close DCS.

I tried this same experiment on Star Wars Squadrons in VR and this did not happen.  I maintained a smooth and steady 120FPS in game play, but overhead dropped to the low 60%s.  Dropped frames were very minimal.  This is what I would expect to see.  So my problem seems to be a DCS issue specific issue.

I saw a youtuber that had exactly this same problem on another game.  On his system it seemed to be a bug connected with his audio  Simply changing his audio output from the Q2 headset, to his monitor speakers fixed the issue instantly.   I tried the same but it had no effect.

If I have nearly 100% overhead available, i would think I should be able to max out the FPS.  I'm pretty sure if I can fix this issue it will fix the other VR anomalies I'm having.  Anyone have a clue what's happening??

[diego999]

That's motion reprojection quicking in, or 'asynchronous spacewarp', as Quest calls is. 

You should be not getting that in the main menu though. Maybe it's a bug? The 120Hz mode on the Quest 2 was experimental last time I checked.

What happens if you set the refresh to 90Hz?

 

[PawlaczGMD]

4 hours ago, Granny said:

I've been troubleshooting some issue in DCS on my Quest 2 and I think I may be on to something, but I don't know what to do about it.  I have notice that the DCS FPS counter shows I am getting FPS equal to half of the refresh rate of the Quest 2 headset.  I.e if set my Q2 at 120hz refresh rate I get a solid 60FPS on the counter.  I have heard that's the result of the headset effectively being 2 displays, one for each eye, thus 120/2 = 60.  I think that information is incorrect.  I recently discovered the Oculus Debug Tool and its performance Hud did a little investigating.  

This is what I see, before I load DCS, FPS is green and maxed out,  overhead is green and near 100%,  very few dropped frames.   As soon as the DCS load screen pops up (not even at the menu yet)  FPS instantly drops by half, and the dropped frame counter begins to sky rocker, yet my overhead remains green and near 100%. It stays the way until I close DCS.

I tried this same experiment on Star Wars Squadrons in VR and this did not happen.  I maintained a smooth and steady 120FPS in game play, but overhead dropped to the low 60%s.  Dropped frames were very minimal.  This is what I would expect to see.  So my problem seems to be a DCS issue specific issue.

I saw a youtuber that had exactly this same problem on another game.  On his system it seemed to be a bug connected with his audio  Simply changing his audio output from the Q2 headset, to his monitor speakers fixed the issue instantly.   I tried the same but it had no effect.

If I have nearly 100% overhead available, i would think I should be able to max out the FPS.  I'm pretty sure if I can fix this issue it will fix the other VR anomalies I'm having.  Anyone have a clue what's happening??

We told you this already in the other thread. Your PC is not strong enough to sustain 1/2 of the framerate in DCS, because DCS is very demanding. If your FPS is locked at 1/2, this means async warp is generating fake frames to make up the difference. It doesn't have the data to generate this on the edges, so you see a vibrating effect.

"have heard that's the result of the headset effectively being 2 displays, one for each eye, thus 120/2 = 60."

This is complete nonsense. You have less than 60 real frames because your PC is not strong enough for the settings you use. The headset is interpolating fake frames to pull it up to 60 because that's what it's programmed to do at low framerates with motion reprojection.

You need to lower your graphics settings, or upgrade your PC.

[diego999]

34 minutes ago, PawlaczGMD said:

You need to lower your graphics settings, or upgrade your PC.

 

This, or lower the headset refresh rate to something more reasonable, like 90 or 72hz.

[PawlaczGMD]

1 hour ago, diego999 said:

 

This, or lower the headset refresh rate to something more reasonable, like 90 or 72hz.

He already said in another thread that with 72 Hz he's still in reprojection. He doesn't seem to understand what it does. I recommend reading up what motion reprojection / asynchronous warp is and what it does to the frames.

[Granny]

On 3/10/2024 at 6:12 PM, diego999 said:

That's motion reprojection quicking in, or 'asynchronous spacewarp', as Quest calls is. 

You should be not getting that in the main menu though. Maybe it's a bug? The 120Hz mode on the Quest 2 was experimental last time I checked.

What happens if you set the refresh to 90Hz?

 

120Hz is experimental but I do get 60FPS and the best overall results when its stable but  becomes unstable sometimes in busy scenarios.  90hz is my sweet spot most of the time for multiplayer.  80hzworks but isn't as smooth.  72 is just annoying.  I think its weird that I'm seeing the drop in while I'm just looking at loading screens and menus too.

[Granny]

23 hours ago, PawlaczGMD said:

We told you this already in the other thread. Your PC is not strong enough to sustain 1/2 of the framerate in DCS, because DCS is very demanding. If your FPS is locked at 1/2, this means async warp is generating fake frames to make up the difference. It doesn't have the data to generate this on the edges, so you see a vibrating effect.

"have heard that's the result of the headset effectively being 2 displays, one for each eye, thus 120/2 = 60."

This is complete nonsense. You have less than 60 real frames because your PC is not strong enough for the settings you use. The headset is interpolating fake frames to pull it up to 60 because that's what it's programmed to do at low framerates with motion reprojection.

You need to lower your graphics settings, or upgrade your PC.

Bear with me, I am an amateur with a no budget for an upgrade. I have to live with what I have so I'm trying o max perform my system and I know (becasue I've seen) it can do better than it is right now.   I thought I was onto something new when I discovered the overhead capacity stats yesterday, hence the new thread.  Here are my current points of confusion:

1) You're saying what I'm seeing is Motion Reprojection caused by ASW.  That makes sense except I've been using OpenXR Took Kit's Turbo Mode for a long time, which gives me a big red warning that it disables ASW.   So, is Turbo also a form of motion reprojection or is something else going on?

2) Oculus display tools shows I have in the neighborhood of 97% overhead capacity even before my FPS is cut in half, and it stays there after the cut.   In other games I see a cut in capacity but maintain FPS. If I have so much overhead, why is the FPS getting cut?  It looks to me like my system has more resources and performance available but either Oculus or DCS just won't take advantage of it.   Or do I just completely misunderstand what "overhead capacity" means?

[PawlaczGMD]

1 hour ago, Granny said:

Bear with me, I am an amateur with a no budget for an upgrade. I have to live with what I have so I'm trying o max perform my system and I know (becasue I've seen) it can do better than it is right now.   I thought I was onto something new when I discovered the overhead capacity stats yesterday, hence the new thread.  Here are my current points of confusion:

1) You're saying what I'm seeing is Motion Reprojection caused by ASW.  That makes sense except I've been using OpenXR Took Kit's Turbo Mode for a long time, which gives me a big red warning that it disables ASW.   So, is Turbo also a form of motion reprojection or is something else going on?

2) Oculus display tools shows I have in the neighborhood of 97% overhead capacity even before my FPS is cut in half, and it stays there after the cut.   In other games I see a cut in capacity but maintain FPS. If I have so much overhead, why is the FPS getting cut?  It looks to me like my system has more resources and performance available but either Oculus or DCS just won't take advantage of it.   Or do I just completely misunderstand what "overhead capacity" means?

1) I'm not sure, it might be replacing it with another interpolation method. But having FPS locked at half is a sure symptom of some MR happening.

2) This probably means you're using 97% of your available GPU resources, aka you're maxed out.

The harsh reality is that DCS in VR is extremely demanding, so with your specs you can only do so much to make it run better. Try lowering all graphics settings to minimum and check fps, go up from there.

My current GPU is about 2.5x faster than yours, and I still don't get a good frame rate in many situations (albeit on Crystal, which has a higher resolution). So it is very likely your hardware is struggling. You definitely don't have extra capacity that DCS is not using. I recently had Quest 2 and a RTX 2080 TI, and I was having some performance problems. This is normal on your PC specs.

What I'm trying to convey to you is that your problem is low framerate, not some magical setting or bug you need to find. You need to raise FPS to solve your issues.

You can do it by:

1) buying a new GPU

2) reducing graphics settings in DCS

3) reducing pixel density in Q2.

Anything else is fine-tuning, but is seems like you're not even close with the required performance.

One Hail Mary I saw someone mention would be to use Quad Views Foveated in fixed mode. It decreases the resolution in the peripheral vision of the display, increasing performance. I don't know if this works on Q2, I saw someone use it on Q3.   

[Qcumber]

4 hours ago, Granny said:

1) You're saying what I'm seeing is Motion Reprojection caused by ASW.  That makes sense except I've been using OpenXR Took Kit's Turbo Mode for a long time, which gives me a big red warning that it disables ASW.   So, is Turbo also a form of motion reprojection or is something else going on?

Open XR toolkit does say that turbo can interfere with ASW but I don't really notice it. I tend to leave it on and either lock ASW to 45 or disable it. You can do this through oculus tray tool by setting your own key binds. There are also default keys for oculus app but I don't remember what they are.

As I mentioned in my reply in your other post try setting your headset to 72Hz and reprojection fixed at 36 to see if that is smoother. Alternatively, aim for 40 FPS without re-projection. This is where turbo mode might help a bit. Many people report having playable experiences running at 40 fps fixed with no reprojection. 

As PawlaczGMD says you also need to reduce your graphics settings in DCS. Quad views is also a good option to try as it can give a 30-50% performance boost if your GPU is weaker and you have enough CPU capacity. This does mean that you have to live with a sharp centre and lower res periphery. Play with the settings. If you get the balance right it is a game changer. 

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

 

[5ephir0th]

Tell me you are no trying to achieve 120 fps or even 60 fps with an 1080ti/6700xt at 1.5 PD that you told you have on another thread...

[Granny]

Thanks all for your suggestions and putting up with my lack of knowledge on this stuff.   I was caught in this weird loop where I believe more FPS was the answer, and since FPS seem to always be half my refresh rate, I need to increase refresh rate,  which drove me to try and run at 120hz just to get 60FPS.  I didn't take account the demand my high PD setting had. As soon as I dropped my PD to 1.2, I got all my FPS back, and dropping the refresh rate to 90hz made it smooth, turbo mode made it all pretty stable as well.  I'm getting 80 to 90 very playable FPS now, so that seems to be the sweet spot form my set up.

So here's my next question.  I got to 1.5PD by trying to find a setting the would make my cockpit instruments and such clear and readable.  I have cockpit res at 1040, textures high, and sharpness at 0.9. But at 1.2PD all the text is pretty blurry, anything in my MFDs is unreadable without zooming.  I suspect the problem is TAA but without TAA the aliasing is unbearable (I really hate aliasing).  I had hoped Quadview would help, but I tried that and it gave me a few more FPS but didn't clear up the cockpit display.  Is there anything else I can do to sharpen this up or is it something I'm going to have to live with until I can upgrade?

[diego999]

Have you tried these?

[PawlaczGMD]

2 hours ago, Granny said:

Thanks all for your suggestions and putting up with my lack of knowledge on this stuff.   I was caught in this weird loop where I believe more FPS was the answer, and since FPS seem to always be half my refresh rate, I need to increase refresh rate,  which drove me to try and run at 120hz just to get 60FPS.  I didn't take account the demand my high PD setting had. As soon as I dropped my PD to 1.2, I got all my FPS back, and dropping the refresh rate to 90hz made it smooth, turbo mode made it all pretty stable as well.  I'm getting 80 to 90 very playable FPS now, so that seems to be the sweet spot form my set up.

So here's my next question.  I got to 1.5PD by trying to find a setting the would make my cockpit instruments and such clear and readable.  I have cockpit res at 1040, textures high, and sharpness at 0.9. But at 1.2PD all the text is pretty blurry, anything in my MFDs is unreadable without zooming.  I suspect the problem is TAA but without TAA the aliasing is unbearable (I really hate aliasing).  I had hoped Quadview would help, but I tried that and it gave me a few more FPS but didn't clear up the cockpit display.  Is there anything else I can do to sharpen this up or is it something I'm going to have to live with until I can upgrade?

You can try downloading QuadViews Companion app, and tuning the size, position, and resolution of the high res area. For example, you could try to reduce the high res size, but increase the resolution scaling.

[Granny]

Thanks again everyone for your help, I think I have found my happy place. Its not perfect but I'm in a much better, more playable state than I was a couple weeks ago.  For anyone interested, the final changes I made was to go with 80Hz refresh rate on the Q2, then on Oculus Debug Tool reduced my field of view to 0.8.  This was an effort to preserved some FPS for the next steps.   I increased distortion curvature to High, to focus resolution towards the center.  Then I started inching PD back up, but in the ODT this time, rather than in game.  I don't now why but doing this in ODT seemed to be less of an FPS hit than using the in game slider. 1.3PD is my wall.  With those setting I am getting perfectly smooth 80fps, and readable instruments.  Not crystal clear, but readable.  Still some ghosting and a bit of aliasing but nothing I can't live with. Considering the limitations of my system I am pretty happy. 

 Thanks again. Granny out!