Bad performance (Low FPS) with World Update 3 and new London photogrammetry - possible memory leaks

I also experience random drops in framerate, where the frames suddenly drops from 30 fps (v-sync on) in 4k to 15 fps for 10 seconds up to one minute before it recovers back to 30 fps again. During this period the “manipulator” in developer mode is heavily impacted, and the graphics card almost idles at 30 to 50 percent performance.
I suspect it relates to a data / cpu issue, however I haven’t had this problem until world update 3. The drop in frames seems to happen at random, however maybe when flying close to ground, near an airport, and also flying over area with no photogrametry.
I have tried updating bios and reinstalling the entire computer, however the problem is still there.
My specs are:
Ryzen 9 3900X
Asus TUF RTX 3090 OC
Corsair 4x 16GB 3200 MHz ram
1TB Seagate FireCuda 520, PCIe gen 4
ASUS ROG Crosshair VIII Hero
Corsair RM 1000W power supply

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Hey, I experience similar issues with the A32NX, and am not sure if it is the airplane or the sim yet. Can you try seeing if you get the same fps drop and rebound at the same location again? Also, do you have custom scenery installed in the areas where the drop occurs?

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Yes i also found Out that custom scenery ist causing more chances of slowdowns. For example Drzewieckis Chicago Landmarks. I still think its a vram leak.

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Hi, I am currently checking the drop out using dev mode. The fps drops from 50 to 18 consistently, not any lower not higher. Then comes back up in a minute or so. During this time, the “manipulator” frametime and the mainthread frametime is excessively high (>50ms) from around 10ms during normal ops. This happens on the A32NX custom FBW mode.

It seem to me random and no, I havn’t sceneries installed.

I am also getting dreadful performance when flying low through London only. Not getting this with new york or any of my other dense 3rd party addons. I have to believe this is the result of 2 things. 1) High density in London. Many many buildings and structures. 2) Poor optimization. I don’t think Osobo has enough time to optimize the scenery as the 3rd party creators do. I would love to have this optomized. I love the city, but the drastic drop in fps ruins it for me.

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Something is definitely wrong with this update I ran my game on ultra before and had steady fps 35-40 now I’m getting low 20s

I’ve changed all settings and the only thing that makes a difference is the Terrain Level Of Detail something is definitely bugged with it. My sliders were both set to 100 before the last update. When I drop the slider for terrain level of detail the fps go back to what I was getting before

But when flying the terrain looks terrible my fps was perfect before the latest update I don’t get it

I dropped the UK Photogrammetry and left the blgs. and points of interest alone. I can now fly low at 35-40 fps, and never having been to London I am not the wiser. Happy now.

I’m getting good fps throughout the UK update with the exception of London itself.

Not sure if it’s worth mentioning but I have seen some odd juddering using reprojection (OXR) in scenery where it’s otherwise been completely smooth during the flight - no apparent loading or heavy scenery involved - just appears out of the blue.

I put this down to the use of ‘Automatic’ setting on OXR as I had it on by mistake and I usually fly with ‘Always on’ which has never caused me a problem and it seems to be more efficent.

@sneaky74 Yes this might be the case indeed because sometime it switches between two modes depending on the actual fps and a threshold when in Auto. This is happening with the Index and SteamVR too since WU3. The only explanation I have for now is the FS2020 rendering code is stalling when updating some DX11 buffers and it looks to me these are vertex buffers mostly (per cross checking some settings which are mostly vertex buffer related and the actual glitches at runtime).

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Yep that was my thought also (but without the deep technical knowledge haha). :joy:

Pity as ‘Automatic’ is nice as you get a crisp menu UI as reprojection is clearly not needed there and it can adapt when you’re in heavy scenery - the benefit being you get a clearer image depending on how little the reprojection is being used (x2 or x3 - runtime preview enabled).

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So what puzzles me with London is there are clearly graphical glitches in the scenery - the Thames has these strange reflective spot which appears to be windows to scenery rendered below the London photogrammetry.

It wouldn’t suprise me if it wasn’t just trees they were rendering twice but a completely new layer which should be culled from view.

With SteamVR you can get up to 6 to 1… And it is working with the same quality as WMR motion smoothing now (it used to be under delivering before). This is quite stunning to render at 18fps and display at 90hz with the Index. I didn’t believe it myself at first (and I’m quite accustomed to the tech I guess). This helps flying since WU3 lower perfs in the meantime…

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[World Update 3] Wireframe view of the London mesh reveals very tiny triangles even in the distance
[World Update 3] London Photogrammetry Mesh Holes


Is it possibile to cut off photogrametry in developer mode over London and save it as scenery? Because without photogrametry it looks much better and smooth.

What if they will broke Paris in next update and other big cities?

2070S, 3700X, 32Gb RAM @ 3200

Over London my VRAM is maxed out at 1440p, mostly high settings some ultra. Render scale 100, ground textures at 130.

RAM over London is sitting at 13-14Gb and is stable, I can fly multiple loops and see little change.

FPS holds at 30-40fps even at sub 500ft.

This is pretty similar for me in NY and Tokyo

I want autogen back. Also the colours of photogrametry in London looks bad, it’s also to dark, too much yellow and blue.

I fly Photogrammetry: OFF because the world look much better that way.

In London sure, but there are some places where photogrametry looks very good, USA, SPAIN, ITALY, SWITZERLAND