investigating Large performance drop in VR after updating to 2.8

[Moxica]

This has been a strange few days DCS-wise; Saturday, first hours it looked terrible, and had bad performance. I tried a different setting here and another one there.
Today it looks and performs better than ever. Even the AH 64 in the Falklands was smooth and looked as good as the Falklands map can look that close in my Oculus Quest 2.
Someone has done something very clever.

Edited November 2, 2022 by Moxica

[MPK]

3 minutes ago, Moxica said:

This has been a strange few days DCS-wise; Saturday, first hours it looked terrible, and had bad performance. I tried a different setting here and another one there.
Today it looks and performs better than ever. Even the AH 64 in the Falklands was smooth and looked as good as the Falklands map can look that close.

Is this today's patch? Version DCS 2.8.0.32235.1?

[durp]

It performed better today on a ~30 player server. 
Shadows: Flat and Terrain Object Shadows: Off

However, the aircraft shadows on the ground are gone now, as if I turned off shadows (cloud based  shading including the everything-in-shade quirk was present, so it was not entirely like turning all shadow options to off), so it kinda got better. sort of. 

[Sr.]

19 minutes ago, durp said:

It performed better today on a ~30 player server. 
Shadows: Flat and Terrain Object Shadows: Off

However, the aircraft shadows on the ground are gone now, as if I turned off shadows (cloud based  shading including the everything-in-shade quirk was present, so it was not entirely like turning all shadow options to off), so it kinda got better. sort of. 

I noticed that while the aircraft ground shadow is gone, the vertical stabilizer shadows are still being cast onto the aircraft itself. FA-18 for example. 

[YoYo]

1 hour ago, Moxica said:

This has been a strange few days DCS-wise; Saturday, first hours it looked terrible, and had bad performance. I tried a different setting here and another one there.
Today it looks and performs better than ever. Even the AH 64 in the Falklands was smooth and looked as good as the Falklands map can look that close in my Oculus Quest 2.
Someone has done something very clever.

 

Perhaps lucky shot, but just one ;). Tested - I have not noticed absolutely no improvement (shadows Medium + Flat only). 

Edited November 2, 2022 by YoYo

[zildac]

Just tried the latest beta, and I can without doubt  gain the majority of my 2.7 performance back by simply changing TERRAIN SHADOWS to OFF (in 2.7 I always had them as flat). However, this also removes the shadows under the aircraft and auxiliary equipment etc etc, so not ideal. It does retain the cockpit shadows, which I have always run at medium. One thing I also noticed is that even with canopy reflections set to off (Hornet) I still see the HUD frame reflected in the canopy, which doesn't seem right. So something is still off with the shadows, without doubt. Just to add, rain preset 3 looks stunning in VR with the cloud layers and a strong wind, but there is still some significant aliasing at the horizon in VR.

 

Update: I see no performance increase between TERRAIN SHADOWS - DEFAULT or FLAT.. Only OFF gets me back to 2.7 FPS and even then the GPU and CPU frame times are higher than 2.7

Edited November 2, 2022 by zildac

[MPK]

I just tried today's patch and performance is significantly improved for me compared to the initial 2.8 release. I have clouds low, shadows low, secondary shadows off, terrain shadows off in case that makes any difference

[HeavyGun1450]

17 minutes ago, zildac said:

Just tried the latest beta, and I can without doubt  gain the majority of my 2.7 performance back by simply changing TERRAIN SHADOWS to OFF (in 2.7 I always had them as flat). However, this also removes the shadows under the aircraft and auxiliary equipment etc etc, so not ideal. It does retain the cockpit shadows, which I have always run at medium. One thing I also noticed is that even with canopy reflections set to off (Hornet) I still see the HUD frame reflected in the canopy, which doesn't seem right. So something is still off with the shadows, without doubt. Just to add, rain preset 3 looks stunning in VR with the cloud layers and a strong wind, but there is still some significant aliasing at the horizon in VR.

 

Update: I see no performance increase between TERRAIN SHADOWS - DEFAULT or FLAT.. Only OFF gets me back to 2.7 FPS and even then the GPU and CPU frame times are higher than 2.7

 

https://forum.dcs.world/topic/311147-strange-behaviour-of-shadows-on-28/page/3/#comment-5080258

[zildac]

1 minute ago, HeavyGun1450 said:

https://forum.dcs.world/topic/311147-strange-behaviour-of-shadows-on-28/page/3/#comment-5080258

Yup same behaviour

[Sr.]

54 minutes ago, zildac said:

Just tried the latest beta, and I can without doubt  gain the majority of my 2.7 performance back by simply changing TERRAIN SHADOWS to OFF (in 2.7 I always had them as flat). However, this also removes the shadows under the aircraft and auxiliary equipment etc etc, so not ideal. It does retain the cockpit shadows, which I have always run at medium. One thing I also noticed is that even with canopy reflections set to off (Hornet) I still see the HUD frame reflected in the canopy, which doesn't seem right. So something is still off with the shadows, without doubt. Just to add, rain preset 3 looks stunning in VR with the cloud layers and a strong wind, but there is still some significant aliasing at the horizon in VR.

 

Update: I see no performance increase between TERRAIN SHADOWS - DEFAULT or FLAT.. Only OFF gets me back to 2.7 FPS and even then the GPU and CPU frame times are higher than 2.7

 

Same

Edited November 2, 2022 by Sr.

[KoN]

If I remember when 2.5 dropped we had same problems as we have in 2.8 .

The Lighting was way over the top and shimmer was over done . 

Problems with shadows and big fps drop . 

I'm sure ED will fix the issues. In a couple of years  

Joke aside I'm sure things will be fixed . 

VR is unplugged for now . 

Edited November 3, 2022 by KoN

[YoYo]

9 hours ago, MPK said:

I just tried today's patch and performance is significantly improved for me compared to the initial 2.8 release. I have clouds low, shadows low, secondary shadows off, terrain shadows off in case that makes any difference

We have the dedicated name concerning this - placebo effect :). No any improvements or fixes according offiacial changelog (notice that ED didnt add it yet as the confirmed bug tag in this topic even) and I did few tests and it is the same like it was, so no fixes for this issue still. They are on stage of investigating but not solutions yet. If you want to trully compare use shadows between Low to high and shadows for terreain as default or Flat only. So the same settings like it was on 2.7, not off (temporary solution for downgrade of picture quality in 2.8 and back to 2010 or earlier  ). They need more time and tests.

 

Edited November 3, 2022 by YoYo

[some1]

It's not placebo, just different terrain shadows settings, one has been fixed, the other (flat) was not.

[zildac]

It's not placebo, just different terrain shadows settings, one has been fixed, the other (flat) was not.

I get the same fps drop whether I use Flat or Default for terrain shadows. The only way to get back to 2.7 performance is with Off.

[durp]

It's a bit weird to see such difference between results. 

For the initial release of 2.8 flat shadows were rendered smoothed, which was very taxing on the gpu and cpu.
With the hotfix, the terrain shadows can be set disabled again and the regular shadows set to flat, however, for me it does not render any aircraft shadows on the ground anymore,
hence why the performance (for me) got better (no shadows). 
It's somewhat like turning off all shadows but keep the ground shading by the environment (clouds/sky) enabled so it does not look totally flat but not have any other shadows drawn (aircraft/terrain-objects)

 

 

after the hotfix (duration 157min)

before the hotfix (duration 117min)

in both cases I had to turn off MSAA as it was not possible to run with 2x as with 2.7.

 

this I mean with 'terrain based shading' without shadows this area would be totally unlit (shows also the present issue with the sky based shadows):

 

Edited November 3, 2022 by durp
pasting images adds nullnullnullnull.... blah while(null) {do(Null);}

[YoYo]

btw.

Im using mix of SHADOWS = MEDIUM, TERRAIN OBJECTS SHADOWS = FLAT only

with this mix after yesterday's patch = no any improvements, no issue in 2.7 of course.

but if you use (medium is example from my settings)

SHADOWS = MEDIUM, TERRAIN OBJECTS SHADOWS = OFF (as temporary solution) I agree, I see improvement (maybe not same like it was in 2.7 but is a step forward, just one ;), not two).

ED must to have still to check what is broken however the direction is good.

Edited November 3, 2022 by YoYo

[durp]

I would love to use medium shadows , but DCS runs like ... on an RTX Titan/Threadripper combination, and with the current prices I see no option here to do any game-rig-only build this year.

Edited November 3, 2022 by durp

[Tomcat388th]

I had a game crash and made a ticket just so they would have the info. They suggested that i upgrade my nvidia drivers and with the new drivers I lost 10-15fps in single player 25-31 fps where before I stayed around 40 45 depending on the mission. MP is out with these drivers for me and my low end system.  The old driver which I'm going back to is 516.59

[exil]

7 hours ago, zildac said:

9 hours ago, some1 said:

It's not placebo, just different terrain shadows settings, one has been fixed, the other (flat) was not.

I get the same fps drop whether I use Flat or Default for terrain shadows. The only way to get back to 2.7 performance is with Off.

That's my point! 

In 2.7 you would have noticed a big difference between terrain shadows flat vs default. 

It seems like since 2.8 the flat shadows aren't giving you any performance boost anymore over default. The result is basically the same. 

While I benchmarked between 2.7 default and 2.8 default and didn't see much of a performance loss. 

So my guess would be, that the flat shadows are somehow broken and not general terrain shadows. Since most people used to have them on flat on 2.7 (I did certainly with the rtx 3080) they are now seeing these huge performance drops. 

People should compare terrain shadows defaul in 2.7 vs terrain shadows default in 2.8 and see if the difference in performance is still that huge. If that's not the case we would know that it's the flat shadows that are broken. 

[dutchili]

With 2.8 i was able to put terrain shadows back on with smooth performance. With the hotfix my performance is back down to 2.7 (perceived, not measured).
Also i see more aliasing in the F-16 cockpit and noticed that contrails are back to good looking, but sometimes rendered in below clouds while the plane is flying above the clouds.

So aside from the rendering itself, the 'layer' seems of interest as well.

 

(ocuslus quest 2, rtx 3070, i7, openXR runtime)

 

[WipeUout]

2.8.0.32235.1 gave me less performance than 2.8.32066 with a FPS drop of 9.4% compared to 2.7.

After updating my AMD driver to 22.10.3, my performance with 2.8.0.32235.1 is equal to 2.8.0.32066 which is 7.5% loss in FPS compared to the last 2.7 version.

I use flat shadows only in my test track and settings.

On the positive side, the clouds are really nice now in VR!  Hats off!! 

[Jarmak]

On 10/31/2022 at 9:17 PM, gitbse said:

@BIGNEWY I'd like to add what I found tonight. I did some testing with the same graphics settings, and found that there is a *significant* difference in the performance between models.

My rig:

i9 10900k, 5.2ghz; 6900xt slight overclock; 64gb DDR4, running off m.2 SSD; Valve index. In-game graphics settings are included in a screenshot.

I mainly fly the Apache on MP servers, so I took it so NTTR, instant action. I had very similar performance on this instant start map as I do on MP servers. It was limited to 40fps, no matter what.... however the ctrl-Pause FPS counter showed a frame time of .1ms, consistently.

I then got in the F14, same map. Hot start, instant action. There was an *absolutely noticeable* difference. I could run 60fps no problem, from ground all the way to 40k. Smooth running, no problems. The clouds are still ... eh... but the graphics and the straight out performance is drastically different. Same thing in the F16. Wonderful flying, no stutters, no frames dropped, 60fps solid all the way. Screenshots included of the in-game performance but kinda hard to read. The screenshot with the Mirage is actually from the Apache cockpit.

Same thing happens on my squad's MP servers. There is a significant difference in performance. The Apache (my main frame unfortunately) cannot, and will not break 40fps, sometimes chugging to <30 depending where I'm looking. The 14, 16, 18? Awesome. 55-60fps even on a decently heavy MP server.

Again, the screenshots of the ingame performance tab didn't come out well, but it can kinda be read. You can however see the graph, and the Apache at 40fps is .... somehow holding the same frame time as the others at 60. Odd.

 

I can't emphasize enough the difference between model experiences in game. The Apache visual performance is sluggish, choppy, and at some points bad enough to where it's hard to fly it properly. 20fps is rough in VR. Same maps, both MP and offline, 14 and 16 are excellent. I know there have been mixed reviews from different users from a performance stance for 2.8, but I didn't expect myself to become a benchmark for each side.

 

I can provide better performance screenshots if necessary. I'm not sure how much that performance tab would help in troubleshooting, but I'm ready to help sort this performance issue out. If all VR performance could be like how the 14 is flying right now in game, it would be excellent. For some reason though, different models fly remarkably differently in VR performance.

Having similar issues in the Apache, the CMWS in particular seems to be causing me massive CPU frametime issues. Sitting in parking in and flipping it on and off causes my CPU frame time to nearly double while it's on. Goes bad as soon as the bit test finishes, goes away the second I switch it off. 

[Gravy Jones]

Until DCS starts to prioritize performance, I’m out.  Pretty clouds don’t matter if the basic experience is a slide show if you don’t have a 4090.  No more money from me. 

[freehand]

The VR user's in dcs is about %10 so we are at the back of the que I am afraid.

[HeavyGun1450]

21 minutes ago, Gravy Jones said:

Until DCS starts to prioritize performance, I’m out.  Pretty clouds don’t matter if the basic experience is a slide show if you don’t have a 4090.  No more money from me. 

Turn your terrain shadows OFF now that they were fixed in the latest hotfix, Flat is still broken for now so dont use it as its rendering at the highest setting (default). I was using Flat Terrain shadows prior to 2.8, so switching them to OFF for now temporarily until flat is fixed restored my fps to 2.7 like levels.