Sign in to follow this  
WebMaximus

99% GPU load at dusk in overcast conditions=stutters

Recommended Posts

Overall my performance is really good but one thing I noticed is that if I fly at dusk and there's overcast conditions and I'm above the clouds my GPU load is pinned at 99% and I get pretty bad stuttering. By the time I get lower and almost start descending through the clouds the load decreases and the stuttering issue goes away. I've never experienced this issue when flying under the same conditions but during daytime.

 

I'm using REX Soft Clouds (DX5) and I've tried reducing both the CDD as well as the max upper visibility settings in ASN but to no avail. I've also tried removing some of the shadow options in P3D but still to no avail. I need to find some way to ease off some of the burden on my GPU and I also need to figure out why this only happens when flying at dusk (and possibly also dawn) and not when flying during daytime.

 

Up until now I've been using FIBER_FRAME_TIME_FRACTION=0.01 but I think I'm gonna try to remove this "tweak" and see what happens. IIRC having this set too low can cause the GPU to be swamped under certain conditions. However removing it (or increasing the value) can instead decrease your overall performance so I guess this like many other things will be a balance act trying to find what value works best. If this will even help addressing my issue in the first place, maybe it not related at all to the kind of issue I have.

 

Anyone else seen this performance issue or even better knows how to fix it? Guess one easy workaround is to only fly during daytime :wink:

 

My hardware setup is a 4470K@4.5GHz and a 980 Ti@1455MHz running P3Dv2.5 on a single 4K screen.

Share this post


Link to post
Help AVSIM continue to serve you!
Please donate today!

Have same cpu and gpu with a iiyama monitor @ 2560x1440  ( frames set at 60),  cpu @ 4.4,   no o/c on gpu.
 
test over Washington state with ASN sp3 and Rex soft clouds at dusk.
 
gpu temp 57deg
memory load 1872
gpu load 56%
vas 1138572  ( note only after a few mins )
after a lot of messing around decided to try these .cfg settings I found on the web.

[JOBSCHEDULER]
AffinityMask=252
[bufferPools]
UsePools=1
PoolSize=900000000 ( I know it looks high but have ago anyway)

 

no FFTF

don't seem able to get the memory load above 2350 mb, have tried usepools=0 and lower poolsize .

no idea to the relationship between gpu load and memory load.

 

bob

Share this post


Link to post

I have been playing with monitoring tools for the last couple of days and noticed as my screen is 60 Hrtz, if i lock my frames at 32 (thank you VIC) it drops the usage and the heat of the GPU,  also takes the load of the CPU.  But then again looking at your specs,  there a hell of a lot more powerful then mine,  so i don't know if that would help 

 

 


My hardware setup is a 4470K@4.5GHz and a 980 Ti@1455MHz running P3Dv2.5 on a single 4K screen.

Share this post


Link to post

Richard,

 

Try these settings within ASN

[Cloud options]
PreventTstormsWithCB=1
MinimumCloudDrawDistance=120
MaximumCloudDrawDistance=140
EnhanceIMCConditions=1
HighDetailCBs=1
MaximumCloudLayers=3
[...]
[Visibility options]
MaximumVisibilitySM=15
MaximumUpperVisibilitySM=63
[...]
 
And these settings in Prepar3D.cfg under [Display]
[Display]
[...]
TEXTURE_FILTERING=4
MSAA=4
SSAA=0
VSYNC=1
FXAA=0
TRIPLE_BUFFER=1
TEXTURE_BANDWIDTH_MULT=30
UPPER_FRAMERATE_LIMIT=30
[...]
 
 
Also, pay a visit to NvidiaInspector and delete P3D.exe profile off the list (after a profile backup of course).
If that makes your day, only then, gradually increase cloud layers in ASN from 3 to 8 when cruising in flight levels above overcast, to find the sweetspot.
 
 
Hope this helps.

Share this post


Link to post

Thanks for your input guys, will play around a bit with different settings suggested and see what I end up with.

 

I guess what makes me most puzzled is why I don't see this problem when flying during daytime, it's like the combination of dense clouds and dusk makes my GPU go crazy.

Share this post


Link to post

Looking at the settings in P3D, what would you say are the most GPU-intensive settings?

Share this post


Link to post

Dusk and Dawn have always been heavy on GPU and VAS ... that's another reason I do a lot of testing at those times.  Some things you can try:

 

1.  If you have building and cloud shadows enabled you try adjusting these values in the Prepar3d.cfg:

 

GROUND_SHADOW_TEXTURE_SIZE=1024  (or even 512)
CLOUD_SHADOW_TEXTURE_SIZE=512
 
2.  Reduce cloud density to Medium
 
3.  Reduce AA  (if you're using SGSS AA via NI disable it)
 
4.  Reduce cloud draw distance to 80mi
 
Cheers, Rob.

Share this post


Link to post

Yup - dawn/dusk has always been problematical in both FSX and P3D.

 

 

Vic

Share this post


Link to post

I wonder why that is that dusk and dawn are so hard on the GPU? I would like to think the only difference is another kind of light and other colors but guess it's not that easy.

 

Looks like I might have fixed the issue by disabling all shadows but the internal and external ones and I also decreased the quality from high to medium.

 

I'm not using NI at all anymore and especially not SGSS since I learned by now that is THE performance killer nr 1 when entering dense clouds. Luckily I don't suffer that much from bad AA anymore after replacing my 1080 screen with a 4K TV :wink:

 

I like to keep the CDD in ASN (both min and max) at 110 since the default max upper visibility is set to 100. This to avoid seeing how the clouds are drawn ahead of me. Did try to temporarily reduce the CDD while I was troubleshooting my performance issue but didn't see much of an improvement.

 

Will do some more testing to make sure I nailed the issue using my current settings.

Share this post


Link to post

 

 


I wonder why that is that dusk and dawn are so hard on the GPU? I would like to think the only difference is another kind of light and other colors but guess it's not that easy.

 

Could be that the sim is attempting to display what is not visible to the naked eye. Perhaps what we need is a sky or weather engine that provides variable detail in terms of what is realistic in regard to human vision, and altitude based visibility distance. 

Share this post


Link to post

2 things that helped me

 

1. In nvidea control panel enable "single diplay"  in Multi/mixed gpu acceleration (if you have 1 screen)

2. set frames to unlimited

Share this post


Link to post

Could be that the sim is attempting to display what is not visible to the naked eye. Perhaps what we need is a sky or weather engine that provides variable detail in terms of what is realistic in regard to human vision, and altitude based visibility distance.

Yes, maybe you're right and if the sim indeed is trying to achieve things that we still can't see that of course is a real waste of resources.

2 things that helped me

 

1. In nvidea control panel enable "single diplay" in Multi/mixed gpu acceleration (if you have 1 screen)

2. set frames to unlimited

I already have both these settings the way you suggest but thanks anyway!

Share this post


Link to post

I wonder why that is that dusk and dawn are so hard on the GPU?

 

Multiple texture sets are being blended so increases number of render passes ... otherwise it would look very odd (aka not realistic) to see a sudden change from day texture to dawn textures.  Also another GPU load for dawn and dusk is calculation of shadows, the shadows require more complex calculations as the shadows are MUCH longer adjusting more textures from their cast.

 

Cheers, Rob. 

Share this post


Link to post

Uh oh. I'm nervous now. I've got a GTX 980 Ti SC on the way, and I hope it performs well in 4K!

Share this post


Link to post

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this