3080Ti possibly full vram ?

[dureiken]

Hi guys

When I fly a few times in different missions, I often have a moment where my fps go down and I have a lot of stutter without visible reason.

I tried lowering settings but it's the same. I have a lot of dropped frames and purple spikes in fpsVR. Cpu time is in green.

I have to leave DCS and relaunch it, and even with high settings fps go back to normal.

I am wondering if it couldn't be a Vram saturation ? it's 11.7/12GB.

Note that I have a 12600k + 32GB memory.

Do you guys have this problem ?

 

thanks

[TED]

I've noticed with my 3080 that fpsvr really screws up things! To the point now I have deactivated it as when it's active I get noticeably more stutters. I never had this with my 6900xt. 

My observations now using both 6900xt and 3080 are that the 3080 produces better visuals due to fastwe vram but has less headroom due to less total ram. My 3080 is also constantly close to maxed but when it's working its nicer than the amd. The amd won't play with msaa but is totally stable. 

Another thing I have noticed with the 3080 is that if the reverb hand controllers are active the performance is significantly worse. 

[Rapierarch]

Yes it is a major issue in VR. I believe there is something wrong in the pipeline and DCS loads full set of textures per eye. If I use high textures I have exactly your problem and VRAM cannot be purged by exiting the mission only. 

At this moment using medium only but Hind medium textures are also too big so no Hind for me. Terrain textures does not solve this problem object textures are too big. 

Medium textures are actually fine but the problem is DCS recently moved to 3 levels of textures and old modules like f-5 or Huey does not have medium textures. If you select medium those modules load Low textures where you cannot read any label in the cockpit even with the zoom. 

I hope ED solves this problem soon. Because more modules they add more textures will be loaded in VRAM and soon medium textures will become unplayable too.  

[Mr_sukebe]

Have you tried disabling the Oculus/Steam “homes” that you start in when first putting on the headset?  If not, give it a try as that can free up around 2GB or VRAM

[obious]

On 3/17/2022 at 1:05 PM, Mr_sukebe said:

Have you tried disabling the Oculus/Steam “homes” that you start in when first putting on the headset?  If not, give it a try as that can free up around 2GB or VRAM

How do you do that?

[Mr_sukebe]

Each of them have the option to disable the “home” within their settings.  Probably easiest to look up a YouTube vid on how to do it.

[doclucio]

same problem here,3080ti with i9 10900k and reverb g2.i play well the first mission then for the second one is a purple mess, any idea?!?

[edmuss]

It's an issue with steamvr specifically I think, restarting DCS solves the problem.  Running openxr doesn't have any issue starting multiple missions without a DCS restart, as it's bypassing steamvr entirely it seems logical that's the cause

[Air Joker]

Since two days I´m using OpenXR with OpenXR Toolkit enabled and disabled.

Nevertheless, the same problem occurs again. After some missions the FPS drops from 45 to 15-25 without any reasons being recognizable. The only option then is to restart...

By the way...the Apache always starts with these low FPS and they never go up to 30 or more. I hope this is just the development level...if not, Apache will be 
forever unplayable on my system!

Edited April 6, 2022 by Air Joker

[Supmua]

Check the frametimes with OpenXR toolkit using detailed fps option.  This will tell you whether it is CPU vs GPU bound (numbers are displayed in microsec rather than typical milliseconds), then you can branch out to check RAM vs VRAM usage etc.  I’ve seen RAM use as high as 31.9 GB and VRAM up to 21 GB with my setup.

[Burt]

2 hours ago, Supmua said:

I’ve seen RAM use as high as 31.9 GB and VRAM up to 21 GB with my setup.

Yup same here especially in Syria map. That why everyone is shouting 64gb of Ram and why the 3090 is king.

[dburne]

22 minutes ago, Burt said:

Yup same here especially in Syria map. That why everyone is shouting 64gb of Ram and why the 3090 is king.

 

Hmm thinking maybe I should upgrade my ram from 32GB to 64 GB... I guess depends on how much longer I want to hold on to this system.

[Burt]

That’s one to think about Don, you already have a 3090.

[Supmua]

The question though is whether the RAM hogging tendency like that an intended feature or a bug?

[Air Joker]

vor 14 Stunden schrieb Supmua:

Check the frametimes with OpenXR toolkit using detailed fps option.  This will tell you whether it is CPU vs GPU bound (numbers are displayed in microsec rather than typical milliseconds), then you can branch out to check RAM vs VRAM usage etc.  I’ve seen RAM use as high as 31.9 GB and VRAM up to 21 GB with my setup.

I determined the frametimes with the OpenXR overlay...Apache and A-10CII  standing on the runway in the Caucasus with engines running...and these are their 
frametimes with the same settings:

For me, somethings wrong with the Apache...

[Supmua]

The frametime numbers seem pretty bad. Were you running a default mission or something different?  I typically use the Syria hot start one since it can be fairly taxing once the 2 F-16s start to roll out at the airport.  I’ve seen CPU frametime that high or higher in the Marinaras when flying over the carrier, but never seen GPU in the 50s.  

I normally use the Syria mission to tune my settings so that I can get around 22.2 ms or less for both GPU/CPU frametimes while on the ground. 

[Air Joker]

...both were "Instant Action Missions".

But...after a while (after 10-20 minutes), the A-10's FPS may also collapse for no apparent reason and they won't recover until I abort the mission. Sometimes I have to restart the whole PC...

This is a mystery that I have not yet been able to explain....

[timcat]

Definitely not aircraft specific. This is happening to me on the F18 if I task the system too much (get to close to alot of AI or bomb craters/smoke. FPS drops to 10-15 and does not recover. I have to exit out of DCS.

[Supmua]

Would be interesting to see if your RAM or VRAM is saturated when this happens. 

[timcat]

I'll check tonight if it happens again. By the way, this only started happening when I switched to OpenXR.

[dburne]

9 minutes ago, timcat said:

I'll check tonight if it happens again. By the way, this only started happening when I switched to OpenXR.

Might be a clue there...

[Supmua]

12 hours ago, Air Joker said:

...both were "Instant Action Missions".

But...after a while (after 10-20 minutes), the A-10's FPS may also collapse for no apparent reason and they won't recover until I abort the mission. Sometimes I have to restart the whole PC...

This is a mystery that I have not yet been able to explain....

OK I did testing on that Caucasus hot start instant mission and it surprised me because it was actually more taxing than Syria.  My CPU frametime was 24-25 and GPU 22 ms, so the CPU is the bottleneck in this case.  Now when I turned to the side to look left and right--away from the aircraft shadows, the CPU frametime would drop down into 19 ms range.  The culprit turned out to the the shadows on the runway (pretty complex on the Apache with all those moving blades).  I turned off shadows and CPU frametime dropped down to 17 ms, while GPU frametime instead became a bottleneck at 19 ms.  The frametimes got even better once you're up in the air.  Now imagine placing 10 of those Apache on the same runway using that mission, it would be a stuttering fest.

 

I did not experience high GPU frametime during the test.  Personally, I do not like playing without shadows since we're no longer in those dark ages of gaming but if you're in a pinch for extra framerate in VR then turning off shadows might be the way to go.  I'm also going to test this in SteamVR mode and compare.

 

EDIT:  So with SteamVR OpenVR mode exact same pixel rending (3.6K horizontal), same mission (Apache Caucasus Runway start), flat shadows.  My CPU FT is 29-31 ms, GPU FT is 23-24 ms.  So for me, OpenXR option is still better.  The juddering is also worse in SteamVR mode when fps is below 45.  Strangely, juddering isn't bad at all for me with OpenXR even with framerate in the mid 30s.

 

So far, settings that I've found that can significantly affect CPU frametimes are textures and shadows.  Reducing those settings can help boost my CPU frametime by a good margin.

Edited April 8, 2022 by Supmua

[Air Joker]

Thanks for yor tests .

I noticed something. The OpenXR Motion Reprojection is responsible for the FPS collapse in Apache (and Hind) at my system. If I turn off Motion Reprojection then Apache has 40-45 FPS. As soon as I turn it on again the Apache has 15-25 FPS (same in the Hind)...unplayable!

The second thing that struck me about this...without Motion Reprojection, both screens in the A-10C II (and everything else) are noticeably sharper than with enabled Motion Reprojection.

So far I haven't found a way to do Motion Reproduction together with Apache without having masive FPS drops.

I really like the Motion Reprojection because without it the image stutters noticeably when looking sideways .

 

[edmuss]

41 minutes ago, Air Joker said:

Thanks for yor tests .

I noticed something. The OpenXR Motion Reprojection is responsible for the FPS collapse in Apache (and Hind) at my system. If I turn off Motion Reprojection then Apache has 40-45 FPS. As soon as I turn it on again the Apache has 15-25 FPS (same in the Hind)...unplayable!

The second thing that struck me about this...without Motion Reprojection, both screens in the A-10C II (and everything else) are noticeably sharper than with enabled Motion Reprojection.

So far I haven't found a way to do Motion Reproduction together with Apache without having masive FPS drops.

I really like the Motion Reprojection because without it the image stutters noticeably when looking sideways .

 

Motion reprojection has a GPU overhead cost to it, I think it depends on your GPU but I've seen between 5-9ms.
Watch the postGPU numbers in the OXRDT performance overlay when you have MR enabled for an idea of the performance cost.  I think if you add the appGPU and postGPU figures it represents the total GPU time.

If you have 45fps (22ms) without MR then adding 5ms to that gives you total GPU time of 27ms which puts you firmly in the 30hz bracket, if your total time gets above 32ms then you're going to be dropping down to the 1/4 refresh rate bracket (22Hz) which I think then costs more overhead and will degrade performance further.

Basically I would try reducing some settings to keep the total GPU times higher and/or disable MR.

[Supmua]

No idea about effect of MR on CPU frametime as I don’t have a WMR device, but V sync on the Aero and motion smoothing on SteamVR devices tend to affect GPU more than CPU.