Upgrade to 5.1 Causes Glitched Rendering


After upgrading a small test project of mine to 5.1, the rendering has gone very bad. See image below:

I am trying to find the problem, but so far, no luck. I did get some error warnings:

But I have fixed those errors and restarted the project. I am also using an AMD 6800 xt with the latest drivers of :“Adrenalin 22.11.1 Optional” and on Wondows 10.

Any help would be great!

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Im having this exact same issue, anyone manage to find a solution?

I did enable SM6 and try a range of things from lighting, ray tracing changes and shading changes with no luck.

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Maybe is the same problem here. in my UE5.0.3 everything is perfect, but when updating to 5.1 and change it to shader model 6, every rect or directional light ends up in those strange white squared noise.

As you can see, spot light and point light, as well as path tracing(with all kinds of light), are working fine.

I´m using a ryzen5 2600, 40gbram and a RX6750xt. Windows 10. both directX and amd video drivers updated.

Hey everyone, “happy” to see I’m not alone.
Have same issue described right here

What I have investigated so far:

  • It’s about combo of Raytraced shadows + Virtual shadow maps/Shader Model 6 + UE5.1. On 5.0.3 everything works fine with SM5 and SM6

  • For some reason virtual shadow maps work fine with SM5 in 5.0.3, but refuse to work with SM5 in 5.1.

  • It’s not about light type as you mentioned, but about light radius. If you will take point light and increase it’s radius from 0 it will create same issue.

  • Looks like it’s related to AMD GPU, since we all have it (mine is RX6600, drivers 22.11.2)

  • TEMP FIX: If in UE5.1 you will turn off SM6, turn on SM5, turn off virtual shadow maps and turn on Raytraced shadows - issue will be gone. I wonder it will loose in quality with such settings? (how do I get rid of this noise in the shadows?):

At this point I’m wondering if there is any point in using 5.1? 5.0.3 should provide nearly same lightning quality options without this issues, right? I wish we could tag a UE developer here somehow, because it’s clearly AMD/UE bug.


I remember reading on the forum that from 5.1 up only pure hardware ray-tracing will be supported for newer cards. 5.0.3 was the cutoff point where the 20 series and older amd cards would still be able to use it.

I think it has to due with the switch of architecture in the cards. (probably lovelace & rdna3 on-wards)

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Interesting, still hope this is not related since cards mentioned above here fully support SM6, standard RT (don’t know if it’s “pure” or “fake”) and are 20/21/22 year of release, so it’s kinda stupid.

This also makes me wonder what RT settings in which UE (5.0 or 5.1) should I use to get maximum quality

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I think they were axing pascal support not sure about the amd family.

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Good to know theres a work around if we really want to use 5.1 but yeah it would be great if we could get Epic’s attention on this cause without SM6 you can’t use Nanite which is a huge loss.

There’s really not clear information on this anywhere that I could find.


This is what we found out.

I also have an AMD Card, the RX 6900 XT. Just today I found out about the Source Radius setting on light sources. Turning it down to 0.0 should fix the ray tracing issues. As far as I’m concerned, Epic put out a glitched 5.1 product since 5.0.3 seems to works fine. It’s definitely weird too since I’m pretty sure the latest AMD Driver, 22.11.2, released before UE 5.1 did. I haven’t tried to downgrade my driver to double check. Hopefully the next UE update fixes this issue. Thanks for staying on top of this nuclearpeace!

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Hello there. I tried to downgrade AMD drivers and also tried different versions (pro, or not sure how they call it) but still issue remains, unfortunately. I have an idea about UWP drivers since it has something to do with SM6 and “hardware -accelerated GPU scheduling feature”, which is turned off in common AMD drivers, but didn’t have time yet to check it.
(If someone is interested - you can try it yourself AMD Radeon Software - Preview Drivers - DCH/UWP | guru3D Forums)

P.S. Also keep in mind that setting Source Radius to zero will poorly affect lighting quality and will make it harsh in most scenarios.


Even with the new updates, the glitch with ray traced shadows is still there.

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I downloaded the new UE 5.1.1 and the new AMD Driver 23.2.1 and there has been no change. Enabling the Hardware-Accelerated GPU Scheduler made no difference either. I think Epic Games would have to fix this issue eventually if they plan on supporting games made with UE 5.1 on the Xbox Series X or Play Station 5 since they also have older gpus now.


I tried copying my project over to my laptop with a RTX 3060 but same problem happens for the most part. I think just the fact that the project was built originally on this amd card might be part of the problem but not sure.

Definitely need Epic’s help here.

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I have an NVIDIA RTX 2800 and an ATI Radeon RX 6800 for my desktop and my game is currently building with UE 5.1.1. I’m not currently seeing any issues with NVIDIA, but the ATI card shows major artifacts with ray traced shadows enabled. I can make this immediately go away by disabling it (r.raytracing.shadows 0), so I’ve added a path in my startup Blueprints to check for ATI and run that as a console command while my loading UMG widgets are showing.

For in-editor, you can add an editory utility blueprint to run the console command as well (see Running Blueprints at Editor Startup | Unreal Engine 4.27 Documentation)

r.raytracing.shadows 1:

r.raytracing.shadows 0:

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Still broken in UE 5.2 preview 2. No proper fix in sight.

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It has been fixed in release version of UE 5.2.

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