CPU Bottlenecking in MT and VR - possible Solution - worked for me!

[Leafcutter1008]

Hey guys,

like many others I had the problem that I always got the red notice "CPU bound to mainthread" like many others. 

Turning off motion reprojection in the OpenXR toolkit AND the OpenXR-Runtime solved this problem!

FPS went immediately up from 30 to > 60 with nearly maxed out settings. No stuttering annymore MT works now better than ST. 

Try it out!

I9-10900K, RTX3080, 32GB RAM

I hope this will help you out!

EDIT: Although my FPS went up to nearly 80 (high in the sky) I have to admit after some testing that there is still stuttering and I have the impression that even with much lower FPS (30 -45) in ST the gameplay with activated motion reprojection was much more fluent...and the images are far more crispy...

Edited March 14, 2023 by Leafcutter1008
Edit

[BIGNEWY]

thank you for sharing, personally I dont use motion reprojection 

[Glide]

1 hour ago, Leafcutter1008 said:

OpenXR toolkit AND the OpenXR-Runtime

The toolkit just modifies the OpenXR settings.  If you have Turbo Mode on it will disable MR.  Or, you leave it set to Default in the toolkit and Disabled in OpenXR.  Try turning off shadows and anti-aliasing.  Turn Anisotropic filtering to x16 to help with the jaggies.  Low Terrain Textures and "lower" View Range helps too.

[Leafcutter1008]

Thanks for the advice. I use Anisotropic filtering since a long time at x16 so that seems not to be the solution - maybe without it would be even worse. I have to try out the turbo mode in MT. In ST I once tried it out but it was very bad in comparison with MR... So I hope that it will be possible to make MR work also with MT in the near future cause this feature was a real game changer for me in ST and I don´t understand why it causes a bottleneck in MT...

[flyingcyrus]

3 hours ago, Leafcutter1008 said:

Hey guys,

like many others I had the problem that I always got the red notice "CPU bound to mainthread" like many others. 

Turning off motion reprojection in the OpenXR toolkit AND the OpenXR-Runtime solved this problem!

FPS went immediately up from 30 to > 60 with nearly maxed out settings. No stuttering annymore MT works now better than ST. 

Try it out!

I9-10900K, RTX3080, 32GB RAM

I hope this will help you out!

EDIT: Although my FPS went up to nearly 80 (high in the sky) I have to admit after some testing that there is still stuttering and I have the impression that even with much lower FPS (30 -45) in ST the gameplay with activated motion reprojection was much more fluent...and the images are far more crispy...

 

Smoothness is more a matter of how regularly the frames are displayed than how many...
Motion reprojection sends a perfect steady 90fps (assuming the headset has 90Hz display(s) ) from only 45 actual rendered frames. This is the reason why it is smoother than a framerate running like crazy between 60 and 80.

I'm in VR for almost 3 years now, and I still really can't figure how people can play without Motion Reprojection without dying from headaches, or simply throwing up ! (No offence @BIGNEWY ).

[YoYo]

3 hours ago, Leafcutter1008 said:

Hey guys,

like many others I had the problem that I always got the red notice "CPU bound to mainthread" like many others. 

Turning off motion reprojection in the OpenXR toolkit AND the OpenXR-Runtime solved this problem!

FPS went immediately up from 30 to > 60 with nearly maxed out settings. No stuttering annymore MT works now better than ST. 

Try it out!

I9-10900K, RTX3080, 32GB RAM

I hope this will help you out!

EDIT: Although my FPS went up to nearly 80 (high in the sky) I have to admit after some testing that there is still stuttering and I have the impression that even with much lower FPS (30 -45) in ST the gameplay with activated motion reprojection was much more fluent...and the images are far more crispy...

 

It's obvious that without reprojection you will see stutter, unless you have a computer powerful enough to keep you 100% of the frames above the refresh rate your headset.

Unfortunately, this is not a solution.

[YoYo]

15 minutes ago, flyingcyrus said:

I'm in VR for almost 3 years now, and I still really can't figure how people can play without Motion Reprojection without dying from headaches, or simply throwing up ! (No offence @BIGNEWY ).

Unfortunately, my experience shows one thing, most often they do not know how to test it, and the other group does not realize what it gives and what it is all about. We also have a third group that has a fairly low refresh rate in the goggles, such as 45 or 60, some has 75 (like Pimax). If the simulator (and you have very powerful computer) does not go below this level, you can have MR turned off. But it's definitely (at least for me) not DCS. In fact, in IL-2 I have MR turned off, but there I have frames above my refresh rate (90Hz) in 95% of cases. If this is not met, full agreement, without MR it is impossible to fly for me too.  I tried turning off MR in MT version on South Atlantic map on Gazelle, low flight and without MR you can't fly, just.

Edited March 14, 2023 by YoYo

[Glide]

There are a lot of variables at play here.  In my G2, if I turn up the Shaking Reduction, the wobbles get worse.  I suspect this is because the motion vectors that are used to predict the missing frame are not as accurate. I have the Omnicept version, which has more sensors than the standard G2.  So, although I can get MR working pretty good at 60fps, it may not be the same for other hardware.

[BIGNEWY]

18 minutes ago, flyingcyrus said:

I'm in VR for almost 3 years now, and I still really can't figure how people can play without Motion Reprojection without dying from headaches, or simply throwing up ! (No offence @BIGNEWY ).

No worries, it does not suit everyone for sure and will depend on your hardware. I have never liked using motion smoothing, but I always tweak my settings to get 45fps minimum in VR and now getting much higher.

[YoYo]

7 minutes ago, Glide said:

There are a lot of variables at play here.  In my G2, if I turn up the Shaking Reduction, the wobbles get worse.  I suspect this is because the motion vectors that are used to predict the missing frame are not as accurate. I have the Omnicept version, which has more sensors than the standard G2.  So, although I can get MR working pretty good at 60fps, it may not be the same for other hardware.

Interestingly, recently I checked 60Hz with the DCS-MT version few days ago. I haven't flown that much lately with this refresh rate. And here you can safely fly on the G2 with 60Hz and without MR, the picture is great and smooth, but unfortunately a slight flicker (due to the frequency) is visible, but 90Hz looks better and here the human eye does not see this characteristic screen flicker. It's like TVs. After all, once there was a craze when 100 Hz was introduced, and now everyone has it in their home.

[Glide]

I still run 60hz monitors. Try the sunglasses setting in the OpenXR Toolkit.  I saw another member of the community said that helped with the flicker.

[Leafcutter1008]

The problem seems to be that when MR is turned on in MT you get this "CPU bound to main Thread" thing.

Without MR it is no problem and the fps go massively up. That´s what I don´t understand...

Why does MR not work in MT? 

[trevoC]

Never could stand MR personally.

That being said, everyone has a different tolerance level for flight and VR. You can build this tolerance over time. My wife has little to no tolerance for her eyes seeing something different than her body experiences. I'm fine with it until around <20 fps. Low teens start to make me feel ill.

[YoYo]

13 minutes ago, Leafcutter1008 said:

Why does MR not work in MT? 

? It works, as usual (just in OpenXR).

MR cuts your FPS by half, if the computer does not keep the maximum number of frames at the refresh rate of the goggles, so if you turn it off no wonder the FPS goes up but you will see stutter if you don't have a powerful enough computer.

Edited March 14, 2023 by YoYo

[Leafcutter1008]

vor einer Stunde schrieb flyingcyrus:

Smoothness is more a matter of how regularly the frames are displayed than how many...
Motion reprojection sends a perfect steady 90fps (assuming the headset has 90Hz display(s) ) from only 45 actual rendered frames. This is the reason why it is smoother than a framerate running like crazy between 60 and 80.

I'm in VR for almost 3 years now, and I still really can't figure how people can play without Motion Reprojection without dying from headaches, or simply throwing up ! (No offence @BIGNEWY ).

this is a very good explanation. So this means that every frps above 45 is useless in MR?

There is a function in the Toolkit that allows you to lock the framerate either to 30 or to 45 I think. Could it be the clue to use this function?

vor 2 Minuten schrieb YoYo:

? It works, as usual (just in OpenXR).

and why do I and many others get this CPU bound to mainthread in MT and not in ST? 

[Leafcutter1008]

btw. in 2D I get fluent 180+ fps in MT....no stuttering at all, smooth as butter...

so it can´t be my computer or am I wrong...

[YoYo]

9 minutes ago, trevoC said:

That being said, everyone has a different tolerance level for flight and VR. 

This is different story. Without MR you can see slideshow (more often or less often). It has nothing to do with the fact that someone feels better or worse. Simply experience and immersion are much worse if you don't get a smooth picture. Same as on 2D.

[trevoC]

10 minutes ago, YoYo said:

This is different story. Without MR you can see slideshow (more often or less often). It has nothing to do with the fact that someone feels better or worse. Simply experience and immersion are much worse if you don't get a smooth picture. Same as on 2D.

With MR I see a slideshow because the artifacts pull me into experiencing the display rather than allow it to fall back into the experience as it does without MR IMO.

I have a high tolerance for low frame rates, others do not. It absolutely matters IMO and I was responding to someone who was asking how people don't get sick without MR on. Its because there are different tolerance levels of this.

[YoYo]

1 minute ago, trevoC said:

It absolutely matters IMO and I was responding to someone who was asking how people don't get sick without MR on. Its because there are different tolerance levels of this.

It doesn't matter to me. I always feel the same with MR or without. However, slideshow is something that I do not tolerate for aesthetic reasons. I think it's a subject of expectations. 

My favorite test for checking how reprojection works (or it doesnt work) is test in cockpit, move from left to right (looking straight ahead always) and checking gauges , the second test - very low flight above the ground, trees level, and looking completely to the right or left (your head 90 degrees from straight path of flight) and look on trees .

BUT this is different story (offtopic), not for this topic I suppose. EOT :).

[Glide]

44 minutes ago, Leafcutter1008 said:

There is a function in the Toolkit that allows you to lock the framerate either to 30 or to 45 I think. Could it be the clue to use this function?

Well, in my case, with my headset set to 60hz, it expects 60fps.  If I lock MR at 30fps, then it will create 30 prediction frames to go with the 30 "real" frames.  So, the probability for missed targets is high.  If I could lock the headset at 30hz, and lock the MR at 30, the probability of a "bad" prediction frame goes way down.   I am going to retest MR and try the Unlocked option.

Edited March 14, 2023 by Glide

[Leafcutter1008]

vor 10 Minuten schrieb Glide:

Well, in my case, with my headset set to 60hz, it expects 60fps.  If I lock MR at 30fps, then it will create 30 prediction frames to go with the 30 "real" frames.  So, the probability for missed targets is high.  If I could lock the headset at 30hz, and lock the MR at 30, the probability of a "bad" prediction frame goes way down.   I am going to retest MR and try the Unlocked option.

 

I could never play with 60 Hz...I tried this one time and the flickering made me mad...there is such a huge difference between 90 and 60 Hz in my opinion

[av8orDave]

1 hour ago, YoYo said:

This is different story. Without MR you can see slideshow (more often or less often). It has nothing to do with the fact that someone feels better or worse. Simply experience and immersion are much worse if you don't get a smooth picture. Same as on 2D.

Not sure I agree on this one. In my case, the experience is subjectively worse with motion reprojection than it is without. When I enable MR, the "jelly" or "wiggly" effect seen around the edges of the cockpit, HUD, or rotors in the case of helicopters are all very immersion breaking. The "ghosting" effect seen on wingtips when banking is another effect that is a real problem for me. 

Without MR, the slight "stutter" that you occasionally see is much less distracting or immersion breaking than the effects seen with motion reprojection. Another case of "to each their own" I suppose.

Edited March 14, 2023 by davidrbarnette

[trevoC]

Just now, davidrbarnette said:

Not sure I agree on this one. In my case, the experience is subjectively worse with motion reprojection that it is without. When I enable MR, the "jelly" or "wiggly" effect seen around the edges of the cockpit, HUD, or rotors in the case of helicopters are all real immersion breaking. The "ghosting" effect seen on wingtips when banking is another than is a real problem for me. 

Without MR, the slight "hiccups" that you occasionally see is much less distracting or immersion breaking than the effects seen with motion reprojection. Another case of "to each their own" I suppose.

This is my experience more than the other.

To each their own. Clearly there are wildly different experiences based on all types of variables.

[Glide]

So, MR unlocked worked like a charm in the f-16 and I did not notice any rotor wobble in the ah-64 as I was struggling to get it airborne (something up with my controllers, I think).  This is because with my settings I can maintain 60fps in VR, so very low probability of bad prediction frames.

55 minutes ago, YoYo said:

My favorite test for checking how reprojection works

Another easy test, enable the OpenXR toolkit FPS counter.  With MR disabled, panning the headset back and forth, you will see double vision in the letters.  With MR enabled, it's perfect.

[Glide]

Tested the AH-64 again, with working controllers, and I could get wobbles if I look up at the clouds with the IHADS displayed.  Workaround: turn off clouds.