UE5 Lumen - suggestions to optimize frame rate?

Hello all,
I am looking to improve the frame rate for my above UE5 project, which looks much better using Lumen and no precomputed lighting. My computer is a 2080 ti / 3950X / 32GB RAM at 3200 mhz.
Each 2x2 light and recessed strip light has an associated rectangular light. Inside, I get 25-20 FPS using the default Lumen quality settings. Outside is a terrain, with some Speedtree trees. Glass is single-sided “RT” materials, from the Twinmotion pack.
Do I simply need to upgrade my GPU? I realize that Lumen requires top-tier hardware. Thanks in advance, making sure I am not overlooking any easy performance improvements.

Lumen seems so much higher quality than GPU Lightmass or CPU on Production.

You really need to profile your scene to see where your performance is going. Without that information there’s really very little anyone can do except guess

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Lumen can certainly be optimized, but there will be scalability costs to any consideration you make. First questions:

  • Is your lumen set to software or hardware?

  • If hardware, do you have hit lighting enabled?

  • If hardware and using 5.1, do you have high quality translucency enabled?

  • What are your lumen settings in the postprocess volume?

  • Are all assets that support nanite set to nanite?

  • What’s the roughness value of your rougher/glossy reflective surfaces? Is it finer or rougher than .4?

  • Do you have material ambient occlusion enabled?

If you can figure out the answers to these questions, then there are certainly options to improve your performance. Lumen can be optimized quite well in my opinion, but it often requires evaluating and tweaking your assets and potentially your pipeline. Furthermore, your desired quality tier has big implications for performance.


Thank you both, that’s the sort of information that I was looking for. I’ll give those a try.

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