Terrain LOD - What had Asobo done with it in the latest SU?

So we all know that before we could easily push the Terrain Level of Detail to 400 and some could have gone further by editing the CFG file.

Now with SU9 we can barely push beyond LOD 150 without getting terrible performance, and more importantly severe CPU stutters when panning (especially on the ground).

From my point of view the ground and terrain looks pretty much the same as before SU9. So i am really wondering what have they changed to make the terrain LOD so bad on performance ?
Is it simply just a bug or bad coding ?

One of the most annoying things about having the LOD low is the night lights. Now that orange sepia image is visible from a very low altitude and with airliners its simply look bad again.


There are sometimes I have terrible performance on the ground and a restart of the sim fixes it, or just playing on a different day fixes it, as if it’s a network/server issue.


I doubt the problem is the server. Server just sends to you the elevation data (which hights at which coordinates) and which objects at which locations but the computing to turn that into a mountain or a city is done locally on your PC, so that is what drives the real effort. Once the data is sent it just gets updated over time but only the new portions (not yet rendered) is what server needs to send to you as the others are already stored on your PC to render the current scene. Indeed if you monitor your network data usage you will see that normally no more than 200Mb are being used while game is running and only full network speed is used (if required) when updates happen or in photogrametry areas, and that again happen every several minutes typically because once the scene is rendered you already have the data stored. Those updates include terrain but also the rest of scenery, weather and AI traffic.

The problem with SU9 appears to be that CPU usage has been dramatically reduced for some reason I can´t imagine, as before it worked perfect. Good CPU usage together with good GPU too was the combo allowing to render well detailed scenarios at high distance with still high FPS prior to SU9 and SU8 indeed.



You guys guessing SU10 will bring the performance back to what it was ? As the reports about this issues still marked as “being investigated”

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The graphics quality and the textures, the variety and quality of houses and terrain mesh has probably been enhanced.
We should be thankful when Asobo bestows us with even more photorealism :slight_smile:

I just hope this is the result of an intermediate step before DX12. If not we are totally lost. We really need a good and well tested SU10. The last two months have been terrible. Worst gaming experience ever since game was lauched (at least on my side).



I honestly don’t think I will enroll to the beta this time… last time I reported some bad issues straight from the beginning and they anyway went live… :frowning:


Same here :confused:

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Maybe they try to get the graphics quality back to pre su5 standards because many complained graphics were bad after su5 right? Now when they maybe do that we start to beg them reduce graphics quality again to have more fps. Maybe we had the best performance and graphics right from release 2020? And we wanted even better because we are never happy. I had good performance and graphics at release. I could run it smooth on both my old pc and new pc with different settings.


You mean in the rolling cache ?

Don’t want to be pessimistic but I won’t be surprised if SU10 doesn’t change performance drastically. They’ll probably use it to enhance the sim further.

No. I meant in the downloaded data and in your memory. Rolling cache is only used if you plan to fly offline over an area (the one which is cached). I don´t use rolling cache at all. Once you launch flight this long loading time is used (among other things) to download the data for the first render of the scene. Indeed if you teleport afterwards you will see that game needs some time to redownload the new data but this usually takes just some seconds and scene is rendered again into full detail by your system quite quickly.



I dunno, they don’t sound very positive in the Dev Q&A’s when its brought up

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BTW, this behavior when it stutters while panning on the ground reminds me the same stutters we had on the first pre-cache implementation. Then they released the option to select Ultra and it solved it. But now it appears its back again even when Ultra is selected.

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I get the feeling that TLOD is a symptom of a broader problem. As they keep adding more complexity into the flight model/weather etc. these are adding more strain on the main thread. Thus TLOD/AI Traffic and flying complex airliners all get impacted more and more.

Unfortunately, the only controls we have at our disposal to reduce pressure on main thread is to reduce TLOD, reduce or turn off AI Traffic, turn off live weather or fly simple GA aircraft. Not ideal if you want to fly Fenix/PMDG etc. in nice busy airports with atmospheric live weather :frowning:

As they add more complexity, they need to ensure they optimize in parallel - perhaps they are banking on DX12 helping here…


Has it been confirmed then that SU9 affected most people’s performance? Does this apply to VR and flatscreen?

I only fly in VR and didn’t fly for a week as I was busy. The last couple days I’ve had opportunities to fly but my performance in VR has noticeably dropped, such that I had to drop my terrain LOD from 150 to 130 to maintain the same performance as I had previously.

I always feel better if its a known issue. At least I’m not going mad lol.

Try turn off AI-trafiic? When i have Ai on i feel ai-traffic is more alive now than ever before. I think that has affected cpu load on ground as well. I preffer turn off traffic rather than terrain. Ai-traffic is not good anyway and make sure it’s main-thread that is limited. If it’s GPU then reduce render scaling or res

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Microsobo hides the survey results and I believe it’s because they are afraid of people seeing the negative results.


Yep, I’ve had to turn down TLOD, it’s a double whammy because even keeping the same LOD setting the draw distance is massively reduced, so it costs more performance now and is less good quality. Fairly typical of the ‘progress’ made to this sim since release. In my experience every update has been pretty much a downgrade and I wish the sim was as it was on release.

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I also suspect that METAR injection and those transitions are another key factor that eats into main thread.

For anyone that knows Rex will be familiar with the fps impact when trying to smooth out transitions.