Performance issue after update from 5.0 to 5.1


today I upgraded my project from 5.0 to 5.1.
The overall upgrade seams successful, but I noticed a huge performance issue in the editor and if I run the game in the editor (or standalone from the editor).

I changed none of my settings, what can cause this huge impact with the performance?
If I’m not moving, the performance seems to be ok, but soon as I start to move, the frame rate drops to 10-15 fps (frame time).

I also noticed that the shader preparation is often running, how can I compile all shaders beforehand?

My Specs:

Unreal 5.1. (source build)
Ryzen 7 3800X
64GB Ram
GeForce RTX 3060 with 12 GB (drivers are up to date)

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I’ll lay money it’s Lumen.

Do a GPU profile ( CTRL-SHIFT-, ) and take a look at the ‘big’ bits.

My framerate on one level went from 80 to 30. I fixed it using the Lumen overview. In my case, the surface cache was getting ‘too friendly’ with some hedges I had. I configured the leaves to not contribute to distance field lighting, and things were much more near normal after that.


Short question.
How do I do that?

Do I have to adjust the settings in every shader that is used for leaves (thin foliage)?

I turned off ‘affect distance field lighting’ on the leaf mesh. Because I only wanted the basic hedge shape to be used in calculations.

The best thing is to look at your scene in the Lumen overview. It should look roughly the same as the actual scene. If it doesn’t, then it’s time to track down what’s going on.

I was able to Track it down to the raytracing in combination with the Lumen Global Illumination.

I think unreal tried to raytrace something on every surface in my gameworld (open world)

After I disabled the hardware raytracing the in the Project Settings, everthing seams working like normal again.

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Similar problem, and resolution here. Weird thing is works fine turning hardware tracing back on again.

I have the same problem but I couldnt fix it, editor works at 120fps, but I press play and drops to 10fps, I disabled lumen and hardware raytracing.

Yeah, there’s a lot of ‘strangeness’ going on with 5…

If it’s only low on play, that does sound like some code getting out of hand?