VR - Alt-Tab (Window in Focus vs Window Out of Focus) GPU Utilization and Performance

[Pand]

Ok @DCS - I think I found something wrong--- not sure what it is or how too fix it, but it is likely what is making my DCS experience suck.

CPU: i9-12900K
GPU: GeForce 2070
Headset: Odyssey+ WMR - Motion reprojection: ON or OFF is irrelevant - results are the same either way.

In normal operation (as all of us do), the DCS window will be in focus while in VR.  
The game mostly runs a little janky and FPSVR reports it's using about 80% of the GPU being used.

If I then Alt-TAB out of DCS, and DCS is out of focus, I can still look around in the VR headset.  DCS does not take inputs so you can't actually maneuver the aircraft; however, FPSVR reports around 95% GPU usage and looking around and looking at terrain, or things exploding is SUPER smooth.  I mean the best I've ever seen smooth in VR.

 

If I Alt-TAB back into DCS, it goes back to about 80% GPU utilization, and gets janky again.

 

Just sitting on the tarmac, there is roughly a 10 FPS difference when the GPU uses around 95% vs 80%.  Any thoughts on what is going on here and how to fix?   Images attached.

[despinoza]

Same happened to me. 

[noxyd]

I haven’t tried the Alt Tab trick but my GPU usage in game is also low (70-80%) while my CPU usage is low which drives me nuts (12600K, 3080Ti).

if anyone has a fix for this I’ll take it

 

thanks !

[Pand]

Is this the correct place to report this?   How would I engage someone from ED to investigate/troubleshoot?

[despinoza]

I would love to see if ED can replicate this abnormal behavior

[edmuss]

Are you running at 90 or 60 refresh rate?
Top image is showing 17.3ms and 42 fps, but 17.3ms equals 58fps not 42; assuming that you have smoothing engaged the fps counter can't accurately record the fps - I'm going to surmise that the fps was jumping about the 45fps locked down by the half refresh rate.  When smoothing is engaged the GPU usage is reported as reduced, I'm not sure if it actually is or not though.

I don't know if smoothing is disengaged when alt tabbed but assuming that it is then that would explain the fps counter showing the correct frame rate for the frametime (20ms = 50fps) and because the GPU isn't being tied back is capable of more utilisation.  The view will be smooth because it's a static image, the stutters only occur when the frames can't be generated fast enough to keep up with the refresh rate of the panels and head movement is combined.

It looks like you're running 90Hz refresh rate, however with WMR unless you can consistently hold less than 20ms it will disengage the smoothing and it will be stuttery.  Try running at 60Hz and you will be able to have smoothing engaged down to 30ms.

[Pand]

Thanks for the reply!

Although I don't have the screenshots --- it happens with and without motion reprojection.   You might be right about the smoothing; however, I don't have any steam SS or anti aliasing enabled.  I only have pixel density at 1.3 which is barely usable. 

I can visibly see the smoothness difference when alt-tabbed out.  Looking around in VR while alt tabbed I can noticeably tell the difference in smoothness, as well as seeing no degradation in fidelity..... give it a try, everyone I talk to says they experience similar results. 

I'll try the 60hz to see if it will appease the motion reprojection gods  Cheers and thanks for the idea

[JimEb58]

Took about a yr hiatus from DCS, now it's completely unplayable for me with the constant stuttering.  Spent the last month tweaking settings, following every "optimization guide", updating every driver on my PC, etc.  I can run other VR games no problem, but DCS is no joy.

I can run with settings that don't even make my hardware break a sweat, performance graph is easily in the green and still stutters.  Change focus and everything is smooth and beautiful.  Change focus back and pilot resumes having seizures or something.  I've even systematically gone through and tested every graphic setting in DCS, nvidia, steamVR, etc and nothing seems to make a difference.  At this point all I can think of is it's a bug in DCS.  Not going to waste anymore time with this exercise in frustration until DCS has a bug fix or someone way smarter than me discovers a work around. 

AMD Ryzen 7 3700X, 32.0 GB ram, nvidia GeForce RTX 2060 SUPER, HTC Vive

Wonder if the issue is Win 11.  My PC auto updated months ago so I'm way past the window of reverting.

[Steel Jaw]

Interesting info.  The fact remains though that VR in DCSW is a huge trade off and compromise from 2d with TIR.  Theres times I just want smooth gameplay and have to pancake it.

[edmuss]

2 hours ago, JimEb58 said:

Took about a yr hiatus from DCS, now it's completely unplayable for me with the constant stuttering.  Spent the last month tweaking settings, following every "optimization guide", updating every driver on my PC, etc.  I can run other VR games no problem, but DCS is no joy.

I can run with settings that don't even make my hardware break a sweat, performance graph is easily in the green and still stutters.  Change focus and everything is smooth and beautiful.  Change focus back and pilot resumes having seizures or something.  I've even systematically gone through and tested every graphic setting in DCS, nvidia, steamVR, etc and nothing seems to make a difference.  At this point all I can think of is it's a bug in DCS.  Not going to waste anymore time with this exercise in frustration until DCS has a bug fix or someone way smarter than me discovers a work around. 

AMD Ryzen 7 3700X, 32.0 GB ram, nvidia GeForce RTX 2060 SUPER, HTC Vive

Wonder if the issue is Win 11.  My PC auto updated months ago so I'm way past the window of reverting.

You should be able to run DCS vr without any major issues. If the performance graph is green then you should be buttery smooth all round. I even had it smooth with the G2 on a 1070 albeit with some reduced settings, mainly resolution.

Is it stuttering all of the time or only when you move your head, particularly looking out of the sides?

[Pand]

Is there anyone from Eagle Dynamics that can help me troubleshoot this? 

The game in VR runs absolutely beautiful as long as "WINDOW IS OUT OF FOCUS" --- as soon as you Alt-Tab back in so you can actually control the plane with inputs, it stutters like I'm running on 20 year old hardware. 

Cheers

[average_pilot]

Same thing. I've been noticing this for some time and every time I do some googling out of frustration I get the same results with no fix or suggestion that works, and not even some sort of theory about the reason this happens. Extremely frustrating.

Edited March 4, 2022 by average_pilot

[average_pilot]

I was thinking about a possible cause. I wonder if, perhaps, the mirror view is messing with Window's process scheduling, which is already not that great for games to start with, and less so for VR.

[obious]

@BIGNEWY are you able to give this a try and share your experiences at all?

Thanks

Edited March 17, 2022 by obious

[Burt]

Sometimes it just a WMR update that makes things run like crap. I recently had to do this and it solved my issue. 

 

[TylerPL666]

On 1/28/2022 at 6:55 PM, Pand said:

In normal operation (as all of us do), the DCS window will be in focus while in VR.  
The game mostly runs a little janky and FPSVR reports it's using about 80% of the GPU being used

Had same. Turn off HAGS. Should help on "better performence when DCS window out of focus".

 

2nd: Use DCS build fps counter. DCS do not like beeing stalked by any external FPS software.

 

3d. My image on Samsung Odyssey + looks much more clean in Performence/90Hz settings in WMR.

150% in OXR Devtool, Clam bias, MFAA ON, ALL other: MSAA OFF, AF OFF, FXAA OFF, Trilinear OFF... all off! NvidiaPanel: Prefair max performance, Quality: Best performance [be awere that Trilinear have tendention to auto-switch to on when swiching quality]

Textures and Vis Range Medium, 1024, others on Low.

 

Then tell me the fps.

Edited April 26, 2022 by TylerPL666

[Delta59R]

On 2/3/2022 at 10:35 AM, edmuss said:

Are you running at 90 or 60 refresh rate?
Top image is showing 17.3ms and 42 fps, but 17.3ms equals 58fps not 42; assuming that you have smoothing engaged the fps counter can't accurately record the fps - I'm going to surmise that the fps was jumping about the 45fps locked down by the half refresh rate.  When smoothing is engaged the GPU usage is reported as reduced, I'm not sure if it actually is or not though.

I don't know if smoothing is disengaged when alt tabbed but assuming that it is then that would explain the fps counter showing the correct frame rate for the frametime (20ms = 50fps) and because the GPU isn't being tied back is capable of more utilisation.  The view will be smooth because it's a static image, the stutters only occur when the frames can't be generated fast enough to keep up with the refresh rate of the panels and head movement is combined.

It looks like you're running 90Hz refresh rate, however with WMR unless you can consistently hold less than 20ms it will disengage the smoothing and it will be stuttery.  Try running at 60Hz and you will be able to have smoothing engaged down to 30ms.

My understanding. it's taking 17.3ms to draw a frame. The 42 vs 45 could be why its not smooth (some type time/alignment/buffer glitch??). So if its 42 why doesn't it show23.8ms? Because its capped at 45fps and it doesn't need that much time to draw the frame, that's why the gpu is only at 80%. If the gpu was at 100% you would see something closer to 23.8ms bc it using every bit of the time it has to draw the frame, or if it was at 45fps/100%cpu you would see something close to 22ms. For example, if you are sitting at the home/menu screen (for me) its common to see something like this; 45 fps, 6ms, 45% gpu usage.

[Delta59R]

On 1/30/2022 at 9:40 PM, noxyd said:

I haven’t tried the Alt Tab trick but my GPU usage in game is also low (70-80%) while my CPU usage is low which drives me nuts (12600K, 3080Ti).

if anyone has a fix for this I’ll take it

 

thanks !

Thats good. Its probably because its hitting the frame cap. Same reason why usage goes down on the home/menu screen. It doesn't need 100% to reach its goal. Just like why you don't have to keep a Lambo floored to maintain 60mph..