Map Performance

[Biggus]

@Czar66 don't be disheartened.  It's a fairly nasty issue to diagnose.  I've had plenty of moments where I've thought I've isolated a cause, only to have it reappear not long after.

[Joe1978]

@Czar66 The map still has a terrible performance with almost any DCS aircraft and with helos... it's better to leave it.

Now that we know more about the development of this map, I highly doubt that the supposed tests were done with a 2080. 

I've had this rig since before SA came out and the performance has ALWAYS sucked (9900k+3080+64Gb RAM)

We can only hope that Orbx fixes it "in the future"

[Czar66]

15 hours ago, Joe1978 said:

@Czar66 The map still has a terrible performance with almost any DCS aircraft and with helos... it's better to leave it.

Now that we know more about the development of this map, I highly doubt that the supposed tests were done with a 2080. 

I've had this rig since before SA came out and the performance has ALWAYS sucked (9900k+3080+64Gb RAM)

We can only hope that Orbx fixes it "in the future"

GPU model doesn't matter as the performance is inconsistent bellow 900ft in the same scenarios. This is why the 'optimization' word is not being thrown around. It is a bug somewhere.

[Joe1978]

hace 1 hora, Czar66 dijo:

El modelo de GPU no importa, ya que el rendimiento es inconsistente por debajo de los 900 pies en los mismos escenarios. Esta es la razón por la que la palabra "optimización" no se está lanzando. Es un bicho en alguna parte.

Iit's not the GPU itself, but the way the map uses the available Vram/Ram.

 

[Holbeach]

Here's my story so far. 3 days of repeat missions with F4.

Using Falkland AA mission and previously posted settings. No 900' ball drop on return from high altitude after shooting 2 Bears at 26000'.

Added more air sea and land units. Frame drop, but no ball drop.

Added SSAO and SSLR. Total frame drop 62 to 52 on Stanley runway. Still OK. No drop.

Raised, Unit Texture, from Medium to High, (which brings it back to my original overall High settings) and I get a 75 to 20 frame drop at 900'.

Go back to Medium from High and no drop occurs. Repeat tested with F4 and F1.

I can only conclude that something happens at 900' that affects unit texture and sends the GPU to 100% and overload and it cannot produce more than 20 fps. With my GTX 1070 it was 17 fps.

My PC is old, but it works very well with DCS and I don't intend to throw upgrade money at a problem that shouldn't exist.

..

 

[Holbeach]

No ball drop.

 

 

Ball drop. Spot the difference.

 

[Czar66]

6 hours ago, Joe1978 said:

Iit's not the GPU itself, but the way the map uses the available Vram/Ram.

 

Omg, I never knew my spanish was that good.

Understood. Thanks.

I have 12gb VRAM on a 3060 locked at 40fps at 1080p. Usually the card hovers at 50% usage. The lock on fps is to remain constant wherever I look and zoom, and it does. Any map, any module.

On the SA map, not even zooming into several trees is needed for this bug to appear.

4 hours ago, Holbeach said:

No ball drop.

Ball drop. Spot the difference.

You should use FLAT terrain shadows. The default shadow mapped taxes the GPU by a long mile from the FLAT without too much visual benefit, especially above forests. Note that your plane will always cast shadow maps (dynamic shadows) on the ground, if I remember correctly. It was all flat a while ago when your plane shadow would be cut in half if cast on a slopped terrain. It doesn't happen anymore.

You can keep SSS (screen space shadows) for the distant views and it will look just as good. Default shadows are very heavy above forests under 200ft. And that I can see is legitimate weight on the GPU as the lower you go, more shadows are drawn and it is a linear progression on the performance.

I don't use default shadows on ground objects so this issue is disconnected to that.

Changing High textures to Medium on a 12gb VRAM card is no go. It doesn't make sense as other scenarios I've made and played pushes the data much heavier than these tiny scenarios on the SA map.

901ft agl =80 fps...

899ft agl = 30 fps... yeah... not normal.

Heaviest scenario I've ever made and played, attached. The issue does NOT occur there. The difference: Other map (Syria). And it is not that light of a map.

 

Eastern Spear.miz

Edited August 30, 2024 by Czar66

[Biggus]

2 hours ago, Czar66 said:

901ft agl =80 fps...

899ft agl = 30 fps... yeah... not normal.

Quoting just this part for emphasis, because it's a perfect description.

Texture resolution change on other maps might produce a gradual reduction in framerates as you descend generally, but not like this.  This is like a switch.

 

I've had so many moments where I've thought I've found a cause, or I've stumbled upon a cure for this issue.  I've come back to this forum to report on my findings, only to have the problem reappear.  There's a randomness to it.  If you load a mission and you don't experience the problem the first time you are under 900ft, you won't get it during the play of that current mission.  If you reload the mission, you might or you might not suffer it.  If you load into a mission and you've got the sub 900ft frame drop, you might get it during the next mission, you might not.  You probably will, though.

The best possible culprit I've heard to explain it is that DCS wants to rebuild some splat textures endlessly under some circumstances.  That would probably explain part of the randomness and the cause for what is often a quartering of the framerate.

[BJ55]

8 hours ago, Czar66 said:

899ft agl = 30 fps... yeah... not normal.

In some Sinai areas I'm having the same issue, the only way for me to avoid stutters is flat shadows w/o AA and LOD<0.8, so I suspect that it's mainly a DCS graphic engine issue (last patch has big memory leaks).

Edited August 31, 2024 by BJ55

[Holbeach]

9 hours ago, Biggus said:

 

I've had so many moments where I've thought I've found a cause, or I've stumbled upon a cure for this issue.  I've come back to this forum to report on my findings, only to have the problem reappear. 

 

I still pucker up, everytime I pass through the 900' layer, but so far I've had no more frame drop.

Vram (ASUS rog strix 2080Ti) and RAM 16gb ( are about the same at 9.5 each).

I can only state what is working for me and I can now start on building my, post '82 Falklamds, AA mission.

 

..

[demonesque]

11 hours ago, Holbeach said:

I still pucker up, everytime I pass through the 900' layer, but so far I've had no more frame drop.

Vram (ASUS rog strix 2080Ti) and RAM 16gb ( are about the same at 9.5 each).

I can only state what is working for me and I can now start on building my, post '82 Falklamds, AA mission.

 

..

I will be interested to see whether as you build up your mission more and more complex, you have to move your sliders further and further to the left to stop the problem happening. 

I think we have almost determined it is not really one identifiable setting causing the issue. My theory is that it is related to a threshold of the amount of load on your gpu as I did not have this problem in 2d but did have it when I switched to vr. I guess I should try a test back in 2d some time and report back. 

[Joe1978]

Ummm I have never had this problem in 2D environment. It only happens when I use VR.

In 2D, Vram/RAM usage is almost halved.

[Holbeach]

17 hours ago, demonesque said:

I will be interested to see whether as you build up your mission more and more complex, you have to move your sliders further and further to the left to stop the problem happening. 

I think we have almost determined it is not really one identifiable setting causing the issue. My theory is that it is related to a threshold of the amount of load on your gpu as I did not have this problem in 2d but did have it when I switched to vr. I guess I should try a test back in 2d some time and report back. 

So today I raised the attackers to 24, 16 F1, 6 MB339 and 2 Bears. Defenders to 3 F4, 2 Frigates, Rapier and 4 bofors.

So there is a choice of F4 runway start, (54 fps), F4 air start, F1 bombers or fighters air start.

Take out the 2 Bears, so you have 6 missiles left to make a choice of target. I've removed bomb drops because they circle and provide easy targets.

Descent through the 900' layer fps remains at 75fps.

To me it all points to, more pc power and the bug goes away.

Do the 2d thing, because it's obviously no fun for you with goggles in this map and it's a great map.

..

 

Edited September 1, 2024 by Holbeach

[demonesque]

8 hours ago, Holbeach said:

So today I raised the attackers to 24, 16 F1, 6 MB339 and 2 Bears. Defenders to 3 F4, 2 Frigates, Rapier and 4 bofors.

So there is a choice of F4 runway start, (54 fps), F4 air start, F1 bombers or fighters air start.

Take out the 2 Bears, so you have 6 missiles left to make a choice of target. I've removed bomb drops because they circle and provide easy targets.

Descent through the 900' layer fps remains at 75fps.

To me it all points to, more pc power and the bug goes away.

Do the 2d thing, because it's obviously no fun for you with goggles in this map and it's a great map.

..

 

 

Well that is still inconclusive. The Mosquito does not have the issue in 2D transitioning smoothly from 160fps at mid altitude to 145 at 20ft as you would expect.

But the F14 still jumps in 2d at the 900ft mark on my rig from 115 fps to 40 fps. So I cant draw any usefull conclusions at all. 

(And no @Holbeach I can't go back to flying flat screen anymore. I'm having too much fun on the dark side)

 

[Holbeach]

I increased the Frigates to 13, (all live), and the Rapiers to 11 groups, (121 vehicles).

Runway start was 32fps. VRAM and RAM both 11.

Shoot Bear, back down to 200'. No drop bug, then repeat with another Bear, then watch the Rapier/Seacat create carnage.

When all 24 planes were destroyed, frames were about 55 down to ground level.

..

[Czar66]

With several test flights now, I confirm the slow down of frame rate bellow 900ft is due to VRAM usage with the map. Issue remained with the Radar option on the Phantom Special tab.

I've tried just the terrain textures to a lower value and no avail, the issue remained with the F-4 module.

On 8/30/2024 at 12:08 PM, Joe1978 said:

Iit's not the GPU itself, but the way the map uses the available Vram/Ram.

 

You, Joe, I think were 100% right. I was just too stubborn with this issue. Thanks.

For 12gb cards, the F-4 + SA map saturates the VRAM enough to cause the phenomenon, despite having had VRAM being used at 100% before in DCS with lower end cards and having no such problem. Things changed, I guess.

To fix this, it is needed to use the medium textures settings Holbeach mentioned, for 12gb cards or bellow. To use high textures you'll need a 16gb or more graphics card.

SA map is VRAM hungry, for sure.

On 9/1/2024 at 8:29 PM, demonesque said:

Well that is still inconclusive. The Mosquito does not have the issue in 2D transitioning smoothly from 160fps at mid altitude to 145 at 20ft as you would expect.

But the F14 still jumps in 2d at the 900ft mark on my rig from 115 fps to 40 fps. So I cant draw any usefull conclusions at all. 

(And no @Holbeach I can't go back to flying flat screen anymore. I'm having too much fun on the dark side)

 

Yeah, the Heatblur birds are known for their heavy textures. And that weighs on the VRAM. Put textures to 'medium' (not terrain textures, the other one) and see if improves.

Edited September 4, 2024 by Czar66

[Biggus]

My VRAM usage does not change.  It remains at 97.6% utilisation both above and below 900ft when set to medium terrain texture quality.

One thing that does change is Direct 3D usage.  Below 900ft, that ends up pegged to 100%.  Above 900ft, it generally hovers between 50 and 70%.

 

If I set aircraft textures to medium, GPU memory usage drops to 90%.  However the frame rate still plummets upon descending through 900ft.

Edited September 4, 2024 by Biggus

[Mr_sukebe]

2 hours ago, Biggus said:

My VRAM usage does not change.  It remains at 97.6% utilisation both above and below 900ft when set to medium terrain texture quality.

One thing that does change is Direct 3D usage.  Below 900ft, that ends up pegged to 100%.  Above 900ft, it generally hovers between 50 and 70%.

 

If I set aircraft textures to medium, GPU memory usage drops to 90%.  However the frame rate still plummets upon descending through 900ft.

 

having your VRAM already maxed out is not telling the full story of what’s going on behind the scenes.

If the map/aircraft textures result in need to load in say 20GB of texture data over a second, then the GPU will need to unload some and replace with other textures.  We know that DCS is already asking for more than 12GB as your current VRAM is maxed out.  
The real question is more about how much is being addressed over a period of several seconds.  That could be anything from 10GB to maybe 40GB and the higher that is, the more file swapping will be needed.  That swap is dependent upon the management of the GPU, data transfer rates for RAM and over PCIe to both the GPU and SSD.

In short, DCS is asking a lot from not just the GPU but also the rest of your PC components.

My hope is that some of the textures can be simplified.

Edited September 4, 2024 by Mr_sukebe

[Biggus]

13 hours ago, Mr_sukebe said:

having your VRAM already maxed out is not telling the full story of what’s going on behind the scenes.

If the map/aircraft textures result in need to load in say 20GB of texture data over a second, then the GPU will need to unload some and replace with other textures.  We know that DCS is already asking for more than 12GB as your current VRAM is maxed out.  
The real question is more about how much is being addressed over a period of several seconds.  That could be anything from 10GB to maybe 40GB and the higher that is, the more file swapping will be needed.  That swap is dependent upon the management of the GPU, data transfer rates for RAM and over PCIe to both the GPU and SSD.

In short, DCS is asking a lot from not just the GPU but also the rest of your PC components.

My hope is that some of the textures can be simplified.

 

I'm just pointing out that dropping texture quality isn't a fix, it's a mask.  I've seen users with 4090s in the past reporting this issue.  I'm not seeing any pagefile usage nor more than a few GB of DRAM usage changing upon triggering the issue.  I know it's not conclusive at all though.  I still suspect it's a faulty shader issue.

 

[demonesque]

@Biggus yeah the faulty shader or similar makes more sense to me too because the other suggestions don't explan why sometimes the problem does not occur and I can get 60 fps at 20 ft agl for a short while every now and then. 

[Biggus]

29 minutes ago, demonesque said:

@Biggus yeah the faulty shader or similar makes more sense to me too because the other suggestions don't explan why sometimes the problem does not occur and I can get 60 fps at 20 ft agl for a short while every now and then. 

I discovered today that when you load a mission and the bug does not occur, you can force it to occur by hitting F10 below 900ft.  Maybe above 900ft too, I haven't tested that scenario.  If I load in and I have a normal frame rate under 900ft, so long as I don't touch the F10 key, my frames stay at a rate that I'd normally expect on other maps.

I'd love to have some guidance from the devs about ways in which we can help gather data to diagnose and fix the problem.

[Joe1978]

The problem when using F10 affects all maps in general. It is a known problem for ED and has to do with the use of RAM.

[Holbeach]

2 weeks now and after about half dozen F4 sorties every day, I consider myself 100% 'Bug Free' or to be more precise, 'free of bug' during that time.

Dropping Unit Texture from High to Medium is all it took. (No visible difference I can detect).

Removing shadows didn't work. Terrain Texture to Low didn't work. These just made everything look horrible.

Nothing I have tried will make the 900' drop reappear, I'm glad to say.

..

 

 

Edited September 5, 2024 by Holbeach

[Joe1978]

Thanks for the report Holbeach but IMHO, lowering the textures is just a "warm cloth", a bad arrangement...

Two years have passed and to this day it is still the worst performing map in all DCS and it remains unfixed. 

Edited September 5, 2024 by Joe1978

[Biggus]

11 hours ago, Joe1978 said:

The problem when using F10 affects all maps in general. It is a known problem for ED and has to do with the use of RAM.

That's true, ram and the loading of a vast number of textures.  The latter of which I think is probably the more relevant part for this bug.

It's a reliable trigger for the 900ft frame drop under circumstances where a mission will load without having the drop occurring.