Question Ray Tracing shimmering and distortions

May 14, 2023
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Hello guys!

Here's the story. I bought a GeForce RTX 4070 graphics card recently. In some games I'm experiencing specific shimmering/distortions with Ray Tracing enabled. These usually show on the border of lighting, in the place where direct lighting gradually disappears (don't know how to precisely describe it). Check out my video from Quake 2 RTX and you'll have an idea of what I'm talking about:

View: https://youtu.be/S04N0WCCYlQ

I experienced similar problems in other games on my previous GeForce RTX 2070 Super (Control for example). I was convinced that this is a side effect of Ray Tracing caused mainly by the fact that the GPUs still don't have enough power to trace the rays bounces enough number of times, but... My friend bought GeForce RTX 4070 (the same model) recently as well and he doesn't have a similar problem! I mean, there are some distortions from time to time, but not nearly as visible as in my case. He uses the same drivers, has a different motherboard and CPU, but I don't see a clear correlation between these two factors and shimmering I'm encountering.

In Cyberpunk 2077 Path Tracing mode the shimmering is almost non existent. It appears only in some rare cases like on the stairs. It's also barely present in Half-Life with RTX mod. I'm perfectly fine if this is a natural thing. But it wonders me why the problem is less noticeable on my friend's GPU. I also tried to change the game options. With anti-aliasing completely disabled it's even worse. The best result gives Temporal Upscaling AA, but it's still clearly visible. I also see in videos on YouTube that people rarely have this problem, at least in Quake 2 RTX.

I already tried different monitor and cables to exclude that this is an issue with any of these. It's not possible also due to the fact that without Ray Tracing there are no distortions. Do you have any idea what precisely might be the cause? Does someone who has RTX graphics card can confirm similar problems? I haven't tested my new GPU in Control, where the shimmering was sometimes very noticeable on my RTX 2070 Super, but I might do so...

I think that it could be some hardware-driver related thing. In theory these could be faulty Ray Tracing cores, but it doesn't explain why some Ray Tracing games don't have this issue or why is it only barely visible there. I'm pretty sure that to some extent it's a natural issue of Ray Tracing. Look at the Nvidia Remix video (1:33-1:48):

View: https://youtu.be/Vg52-HZhrFc?t=93

There's a similar effect visible when editing Morrowind assets in Nvidia Remix. The Ray Tracing shaders fill the scene with a delay. I think that the renderer needs time to trace all the light rays bounces and that's why there are distortions at first. And I'm fine with that. This doesn't explain however why I'm seeing these things notoriously in real time in Quake 2 RTX and my friend doesn't. :) Any help or suggestions appreciated.
 
Last edited:

Lutfij

Titan
Moderator
Welcome to the forums, newcomer! (Ahem, ;) )

If you swapped the GPU, make sure to use DDU to uninstall/remove all GPU drivers(not just the GPU chip maker's drivers) and then manually reinstall the latest GPU drivers off of Nvidia's support site in an elevated command.

I'd look into the motherboard and see if that's pending a BIOS update, following that, if the OS is pending an update. Be sure to do these, prior to running DDU.

For the sake of relevance, can you state the specs to your build like so:
CPU:
CPU cooler:
Motherboard:
Ram:
SSD/HDD:
GPU:
PSU:
Chassis:
OS:
Monitor:
 
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May 14, 2023
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Here are my full specs:

CPU: AMD Ryzen 7 5700X
CPU cooler: Endorfy Spartan 5 (although I don't think the cooler is related to the problem :))
Motherboard: MSI B450 Gaming Plus MAX
RAM: 2 x 8 GB Corsair Vengeance LPX 2400 MHz (this is currently my bottleneck, can it contribute to the distortions somehow?)
SSD: Samsung SSD 980 (system drive) + Samsung 860 EVO (the drive on which the game is installed)
GPU: MSI GeForce RTX 4070 Ventus 3x
PSU: SilentiumPC Vero M3 Bronze 700 W (the PSU has two and half year, but I doubt it's a power issue since in more demanding CP2077 the problem is less noticeable)
Chassis: SilentiumPC Regnum RG4T Pure Black
OS: Windows 11 Pro (newest version)
Monitor: MSI G421V E2

As for drivers, I reinstalled the system from scratch when upgrading my GPU and CPU, so I don't think that the old driver remains are the problem. But of course I can try DDU and install the drivers once again. As for BIOS, it's the most recent version. Maybe the GeForce RTX 4070 has a harder time cooperating with my older motherboard than in my friend's case? He has an Intel Core i5-13600K and an MSI Z690-A Pro motherboard. Now when I'm thinking about this, I suspect that the CPU and motherboard differences may be the key here.
 
Last edited:

umeng2002_2

Commendable
Jan 10, 2022
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That's just the nature of current real-time ray-tracing. There needs to be a lot of denoising to get a coherent image. What you are seeing is some of that noise because no denoising is going to be perfect.

The only solution is to use more rays per pixel/ bounce, but that tanks performance. Since the number of rays depends on the rendering resolution too, using DLSS actually makes the issue worse. These types of artifacts don't show up well on an overly-compressed internet video, so people might be shocked too see how much artifacts there are.
 
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May 14, 2023
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That's just the nature of current real-time ray-tracing. There needs to be a lot of denoising to get a coherent image. What you are seeing is some of that noise because no denoising is going to be perfect.

The only solution is to use more rays per pixel/ bounce, but that tanks performance. Since the number of rays depends on the rendering resolution too, using DLSS actually makes the issue worse. These types of artifacts don't show up well on an overly-compressed internet video, so people might be shocked too see how much artifacts there are.

Thanks for the reply! This explanation convinces me. However I don't understand why on my friend's PC the problem is less noticeable. I just found out that he uses an older version of Quake 2 RTX from GOG. I might check it as well and see if there are any differences. :)