Off Screen terrain pre-caching stutter

When they first introduced this (off-screen pre-caching) feature the sim started running smoother than I had ever seen even with it set to ultra, and the FPS gain was wonderful. Then many people were complaining about draw distance and pop-in (expecting to look through a telescope in zoom and see everything in detail). LOD update was then released and it seemed like every inch of performance gain was lost. I get massive stutter when setting it to anything less than ultra and the performance I once seen, I see no more. At one point the off-screen pre-caching worked like a charm even when turning your view to look behind you. When it was first implemented it was done in what I thought was like an amazing feat. Then the LOD update seemed to broke it, stutters during takeoff and landing came back and no matter what settings you use, low or high they cannot be eliminated.

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Interesting observations. I was testing the low level stutter the other day, and I noticed the tree textures changed as I got close. I set the trees to Ultra, and they stopped changing. I am wondering if the cache and the render settings are out of synch?

Yes even on Ultra there is a stutter when panning around.

It seems to be tracking the sun position, its deffo a strange one but very easy to replicate

DensestSnail693

6m

Do you use HDR? or any GeForce filters?

BlackBag2300

2m

HDR is on but the stutter happens whether it is enabled or not. Im conscious that we are polluting this thread. I have raised an issue for this particular “bug” so will post any further answers on that thread.

DensestSnail693

1m

Does it still happen if the sun is blocked out by clouds?

Addding comments / questions from another thread

@DensestSnail693 Yes it happens with the overcast preset also. Screenshot added showing dev fps counter and stutter.

I’ve noticed this for quite some time. If you reduce your AI traffic and LOD settings (CPU load), the problem is minimized or goes away.

if you follow Grabber’s tuning process here, you can improve your system performance and reduce stuttering.

I do not have AI traffic enabled. performance is absolutely fine other than this particular spot when rotating the camera. This seems to be an issue with the render pipeline. As noted I can change the time at which the stutter occurs by changing the time of day / season etc to change the position of the sun. Possibly shadows. but I cant find a graphics setting that changes the behaviour.

I too have noticed this exact issue, and want to bring it to Asobo’s attention.

This stutter has been a thing since I can remember, but it really didn’t start annoying me/I didn’t start paying closer attention to it until the performance regression that came along in SU7 (pre-hotfix).

I’ve tested the off-screen terrain caching stutter on several PC’s, and it’s there on both Nvidia and AMD GPU’s, regardless of how many or few driver settings I use along with the game.

This issue is semi-related to the MainThread “chug” introduced back into the game by SU7, and only partially fixed in SU7 Hotfix.

I’m currently in the process of narrowing down game settings that make the issue worse with my AMD RX 6900 XT system, with a fresh install of Windows 11 and fresh install of FS2020, with no marketplace addons and no community addons.

So far, the azimuth of the stutter’s center does appear to track the sun’s location and/or time of day, and is most-noticeable when terrain pre-caching is set to “Ultra”.

The stutter is more-pronounced on AMD graphics cards than Nvidia graphics cards (tested RX 6900 XT and 3080 FE), but it’s there on both GPU families. I’ll provide more data as I mess around with FS2020 today.

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Have you tried reducing your LOD to say 50 (as a test)? This makes it go away for me. I’m not saying this is a permanent or acceptable fix, but it reduces or eliminates the issue.

Changing the Lod to 50, the stutter is still there (you can see it in the fps counter) but much less noticeable.

This isnt a performance issue as such, as everything runs absolutely smoothly but for this one very specific stutter.

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That’s interesting, what you say about the trees. Like, just the other day I was sitting on the pad setting up a flight and went into external view and this tree that was in view rather close seemed to like transform from a nice looking tree to missing its leaves and becoming semitransparent. Pretty strange. I could understand this being the case for trees in the distance but for a tree practically right next to your AC, not so much.

My current fix is to run at 80% in game render scaling for both 2D and VR. No more stutters. I have trees back down to Low for both.

Agree with all.

And changing LOD has the same result for me: It minimizes the issue, but doesn’t eliminate the very specific, direction-related stutter when panning 360° continuously around in external view.

What an interesting thing this is… I love Ultra terrain pre-caching, it keeps my average framerate up by a decent double-digit-percent in both PG and non-PG areas, except when it hits that stutter and MainThread chokes on itself.

I would have tested this out on DX12 mode, but DX12’s un-optimized condition right now means it has even more MainThread issues than DX11, though I do wonder if an “optimized DX12” implementation will remedy this issue.

I look forward to more DX11 and DX12 beta flightings!

Im a glutton for punishment so tested in DX12.

Its exactly the same behaviour.

From what I understand, DX12’s current implementation is just DX11’s FS2020 plopped in to the DX12 framework.

That is a terrifyingly gross oversimplification of things, but it works.

DX12 merely opens the door, the fun begins when the simulator’s engine and back-end start to take advantage of DX12’s capabilities; capabilities for which I am very excited to see.

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I did one more round of testing before I reinstalled all of the cities and world updates. Consistent results all around:

  • The “pause” when panning around for me centers on directly-opposite of where the sun is, and follows the time of day accordingly
  • It is in some way related to the Terrain LOD setting, as values above 100 or so make the problem much more pronounced
  • The lower the Terrain Pre-Caching setting, the less pronounced the pause is, but the lower the average framerate is too
  • No other graphics setting affects the stutter

I don’t believe this problem is directly related to the other threads that I’ve commented in about photogrammetry causing a big MainThread hit, but the two are problems are probably related in some way or another.

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exactly the same observations here. Its a real strange one!

I believe this occurs at night also, have you tried that? Not sure if it still relates to the position of the sun?

I have not, but I’ll give it a shot in a little while

It might be more accurate to say the position of the stutter changes depending on the time of day. If I remember correctly there is a period of time at night where it doesnt happen as badly, its around midnight iirc