Hunting for the stutter-free VR experience.

[WipeUout]

4 hours ago, lefuneste01 said:

I do not believe the latency issues you can see in my tracks are created by external processes

Sorry @lefuneste01 for the msiunderstading, I was commenting on in-game stutters in general, not specificaly your track files. 

[Panzerlang]

I had a go with SteamVR, dog's dinner.

Back to OpenXR and I thought I'd play with the Quadview settings in that, to really take a load off the system. I reduced the box to 25% x 25% at 100% resolution. Peripheral to 1% (lol). It looked terrible in the menu but surprisingly not that bad once in the cockpit. 
So, you'd think buttery smooth, right? It was the best so far but still the micro-jerks when looking sideways at low level and really not much different to 35% x 35% and 5% peripheral.

And what's going on with capping FPS to half making the jerkiness worse? "Hey GPU, take half the load off...oh, now you're going ass over tit like you got hit with a quart of bourbon?"

There is something seriously up with the DCS code, I can think of no other explanation.  Having said that, at this point it really is nit-picking because I'm really having to look for it. In actual play the visual experience is more than playable/acceptable. That's in fast planes, I haven't tried the low & slow chopper experience yet.

Edited December 9, 2024 by Panzerlang

[Panzerlang]

I found the FPS counter. It doesn't seem to go lower than 80fps (a lot of "CPU Bound" message). So, I set the FPS limiter to 80, as expected the jerkiness was made worse. Back to max (300) and smoother again.
Unfortunately the counter doesn't appear in the screen-recording I made with Bandicam (replay-track).

I've also set the 2D resolution to 1080p, to see if that would make a difference (thinking a lower-res monitor output for VR mirror might help). I've also tried HMD-Mask. It's like the stutter is baked-in. It can be hugely reduced but not eradicated.

Edited December 9, 2024 by Panzerlang

[sleighzy]

1 hour ago, Panzerlang said:

I reduced the box to 25% x 25% at 100% resolution. Peripheral to 1% (lol)

Which Pimax Crystal do you have? One of the eye-tracked ones? Making those changes using the Quad Views Companion app?

Edited December 9, 2024 by sleighzy

[Blackhawk163]

2 hours ago, Panzerlang said:

I found the FPS counter. It doesn't seem to go lower than 80fps (a lot of "CPU Bound" message). So, I set the FPS limiter to 80, as expected the jerkiness was made worse. Back to max (300) and smoother again.
Unfortunately the counter doesn't appear in the screen-recording I made with Bandicam (replay-track).

I've also set the 2D resolution to 1080p, to see if that would make a difference (thinking a lower-res monitor output for VR mirror might help). I've also tried HMD-Mask. It's like the stutter is baked-in. It can be hugely reduced but not eradicated.

I have the same experience as you do. Super smooth in the middle, but the second I look over to the sides, stu-stu-stutter. It's a small, but very rhythmic stutter. The civ sim and the other combat sim that I play do not exhibit the same issues.  Kinda reminds me of screen tearing. 

[Panzerlang]

3 hours ago, sleighzy said:

Which Pimax Crystal do you have? One of the eye-tracked ones? Making those changes using the Quad Views Companion app?

Original Crystal with eye-tracking. And yes, QV Companion.

[Panzerlang]

1 hour ago, Blackhawk163 said:

I have the same experience as you do. Super smooth in the middle, but the second I look over to the sides, stu-stu-stutter. It's a small, but very rhythmic stutter. The civ sim and the other combat sim that I play do not exhibit the same issues.  Kinda reminds me of screen tearing. 

It's very difficult to see it but the same stutter exists in 2D mode also.

It's like the code of something is failing to send imagery to the headset fast enough and it has next to nothing to do with settings. Yes, the stutter can be made worse with mental settings but even with the load almost entirely removed (all DCS graphic settings set to potato) it still exists. It's very evident with Quadviews disabled but with QV on and potato settings the graphics should flow smooth as silk. But they don't, VR or 2D.

And, given it's a very common experience, it can't be down to a particular mobo, CPU, GPU or RAM etc. Brute horsepower and potato everything, ED need to investigate and sort it out.

[WipeUout]

8 hours ago, Panzerlang said:

It doesn't seem to go lower than 80fps

If your HMD refresh rate is at 90hz and the FPS drops below 90, you will have stutters.  Try lowering your settings in order to have plenty of headroom, try keeping your GPU frametime lower than 10ms.  Of course this becomes difficult in some maps or complex areas like dense forests or cities but most of the time, you should keep at least 1ms headroom.  When you look to the sides, frametime usualy goes up as there is more stuff that needs to be rendered but if you keep your frametime below 11ms (for 90hz/90FPS), then you should not have any stutters, I don't.  Else, there is someting else causing these stutters.  

Edited December 10, 2024 by WipeUout
Typo

[lefuneste01]

For your information, I was very impacted by latency spikes/frame rate drops of a few milliseconds, as I posted before. A BIOS update for my motherboard, which also reset all the settings, resolved everything. I just disabled efficient cores, but keep hyperthreading. Now my fps are far more regular, I do no more have the spikes ! Of course, overcloking is off for the moment, but at least I have a stable basis to start tuning again. 

 

13 minutes ago, WipeUout said:

If your HMD refresh rate is at 90hz and the FPS drops below 90, you will have stutters.  Try lowering your settings in order to have plenty of headroom, try keeping your frametime lower than 10ms.  Of course this becomes difficult in some maps or complex areas like dense forests or cities but most of the time, you should keep at least 1ms headroom.  When you look to the sides, frametime usualy goes up as there is more stuff that needs to be rendered but if you keep your frametime below 11ms (for 90hz/90FPS), then you should not have any stutters, I don't.  Else, there is someting else causing these stutters.  

You can try to use the lower frequency of your HMD (eg 60 Hz for the G2) or use "reprojection" or "smart smoothing" or "motion smoothing" (it depends of your HMD) that will allow you to interpolate frames and so be fluid with half of target fps (45 fps for 90 Hz). But it may introduce some articfacts.

[gonvise]

Hello, very interesting post. Quest pro here.

For me, Quad views FR generates much more stutters than Openxr Toolkit FR. Maybe, as they say, Quad views achieves better pure performance, but at the cost of slightly less performance the Tool kit is much more stutter-free (always, for me). On the other hand, I use ASW at 45 and, until the last patch (fog), putting 50 in the FPS limiter gave me a super fluid experience, but since the new patch we are back to micro stutters when rotating the view. I know perfectly well that the generated FPS are well above 45, since if I disable ASW I have between 60-80 in any situation with my current configuration, which even having a 4090 and a 7800x3d is quite normal since, like you, what I am looking for is fluidity of movement in the VR view.

Edited December 10, 2024 by gonvise

[Panzerlang]

3 hours ago, WipeUout said:

If your HMD refresh rate is at 90hz and the FPS drops below 90, you will have stutters.  Try lowering your settings in order to have plenty of headroom, try keeping your GPU frametime lower than 10ms.  Of course this becomes difficult in some maps or complex areas like dense forests or cities but most of the time, you should keep at least 1ms headroom.  When you look to the sides, frametime usualy goes up as there is more stuff that needs to be rendered but if you keep your frametime below 11ms (for 90hz/90FPS), then you should not have any stutters, I don't.  Else, there is someting else causing these stutters.  

Yes, it is something else. As I said above, with all (ALL) graphics settings set to potato, there are still micro-jerks. 

3 hours ago, lefuneste01 said:

For your information, I was very impacted by latency spikes/frame rate drops of a few milliseconds, as I posted before. A BIOS update for my motherboard, which also reset all the settings, resolved everything. I just disabled efficient cores, but keep hyperthreading. Now my fps are far more regular, I do no more have the spikes ! Of course, overcloking is off for the moment, but at least I have a stable basis to start tuning again. 

 

You can try to use the lower frequency of your HMD (eg 60 Hz for the G2) or use "reprojection" or "smart smoothing" or "motion smoothing" (it depends of your HMD) that will allow you to interpolate frames and so be fluid with half of target fps (45 fps for 90 Hz). But it may introduce some articfacts.

Nope. Capping the FPS (in the headset or in the game's settings), stutter becomes worse. Smoothing, ditto.

[WipeUout]

3 minutes ago, Panzerlang said:

there are still micro-jerks. 

Do you overclock your GPU?  I had some overclocking on my 4090 and tried so many things including re-installing windows to find out that even the slightest overclock was causing stutters as soon as GPU usage was going over 80%.  

[Panzerlang]

43 minutes ago, WipeUout said:

Do you overclock your GPU?  I had some overclocking on my 4090 and tried so many things including re-installing windows to find out that even the slightest overclock was causing stutters as soon as GPU usage was going over 80%.  

Funnily enough I ran that NVidia overclock thing on it yesterday, it gave me around 200 extra mhz. So no, before and after that, zero difference.

[Moxica]

I have identical challenges int the Pimax C Light; Nothing gets rid of that stutter. It is also present in menus.
I've tried absolutely everything., Stutter remain.
FPS is all over the place. From 110 to 35 in same mission.
Now I'm at 72hZ and locked frames at 70. Pretty fluid, but that annoying stutter is there, and does not even show up in the FPS counter..
CPU performance looks like..
 

Edited December 10, 2024 by Moxica

[Panzerlang]

ED have us chasing our tails with this, with zero input. Even if it was only to say "It's our code and we can't fix it", at least we'd be able to quit. Lol.

Here's a question...DCS "now supports OpenXR natively"...does that mean we could use it instead of Pimax' OpenXR? I have no idea how to disable Pimax OpenXR though but I'd like to give it a shot.

[BIGNEWY]

14 minutes ago, Panzerlang said:

ED have us chasing our tails with this, with zero input. Even if it was only to say "It's our code and we can't fix it", at least we'd be able to quit. Lol.

Here's a question...DCS "now supports OpenXR natively"...does that mean we could use it instead of Pimax' OpenXR? I have no idea how to disable Pimax OpenXR though but I'd like to give it a shot.

stutter is very difficult to diagnose, there isnt only one cause. It can be settings, overclocks, firmware, drivers, OS, scripts, controllers, or hardware related ect. 

Everyone has different machines and configurations, we could all ask the question why are most people stutter free? All we can do is look at the data available and try to help people. 

If we get dcs logs and dxdiags, even track replays showing stutter we are happy to investigate it. 

[Panzerlang]

1 minute ago, BIGNEWY said:

stutter is very difficult to diagnose, there isnt only one cause. It can be settings, overclocks, firmware, drivers, OS, scripts, controllers, or hardware related ect. 

Everyone has different machines and configurations, we could all ask the question why are most people stutter free? All we can do is look at the data available and try to help people. 

If we get dcs logs and dxdiags, even track replays showing stutter we are happy to investigate it. 

Hooray! Yes, good point re the stats. I watch a lot of the Big Boys on YT and see a fair bit of stutter in their vids though. My impression is that it's common but people have simply become used to it?

[BIGNEWY]

Just now, Panzerlang said:

Hooray! Yes, good point re the stats. I watch a lot of the Big Boys on YT and see a fair bit of stutter in their vids though. My impression is that it's common but people have simply become used to it?

its not as common as you suggest it is, but when it happens its very annoying and people tend to be vocal about it of course. 

Can you attach your dxdiag also so we can look at other potential reasons. 

[Panzerlang]

1 minute ago, BIGNEWY said:

its not as common as you suggest it is, but when it happens its very annoying and people tend to be vocal about it of course. 

Can you attach your dxdiag also so we can look at other potential reasons. 

How do I generate a DXDiag file? I recall doing it many years ago but my brain chose to bin the detail memories due to decrepitation issues.

[BIGNEWY]

go to windows search and type dxdiag, you should see the app appear, then run it and save the information to your desktop, than attach here. 

thanks  

[Panzerlang]

Me file guvnor. Cheers Newy.

DxDiag.txt

I've just installed some Pimax gubbins, now I see quadviews and stuff in Pimax Play. The next round of experimentation begins...

[BIGNEWY]

thanks can you attach your latest dcs log also, I see your older ones here but it would be nice to have the latest one 

 

[Special K]

@Panzerlang I see a lot of Bluescreens in your DXDiag and that you ran Prime already (which crashed also). It looks that you have some timing issues.

Have not checked the latest BIOS for that board yet, but that is worth to check. On the other hand, check please if you have

- Game Mode disables
- Hardware Accelerated GPU Scheduling disabled
- Core Isolation disabled
- Core parking disabled

 

[Panzerlang]

DCS Log.

dcs.log

[Panzerlang]

24 minutes ago, Special K said:

@Panzerlang I see a lot of Bluescreens in your DXDiag and that you ran Prime already (which crashed also). It looks that you have some timing issues.

Have not checked the latest BIOS for that board yet, but that is worth to check. On the other hand, check please if you have

- Game Mode disables
- Hardware Accelerated GPU Scheduling disabled
- Core Isolation disabled
- Core parking disabled

 

Bluescreens? I had a few some months ago when I was trying to XMP my RAM but zero since. I have Prime? You mean the Pimax thing? Nope. However, just after I uploaded the dxdiag I ran DCS with Pimax' OpenXR and it's the smoothest play yet. Not perfect but to the point where the jerks/stutters could be regarded as pilot buffeting. However, I haven't done anything to disable MBucchia's OpenXR...does the Pimax one over-ride it?

- Game Mode disables I'll google that.
- Hardware Accelerated GPU Scheduling disabled In NVidia control panel?
- Core Isolation disabled Same as the Process Lasso thing? (if so, already done).
- Core parking disabled Ditto line above.

In Process Lasso I have DCS running on just four P-Cores. All E-Cores are excluded from DCS. Four P-Cores gives the least amount of stutter.

Edited December 10, 2024 by Panzerlang