Hi @Ricfm,
Realistically, you shouldn’t be worrying about performance at all if you’re using the Movie Render Queue to render out your frames.
Likely what you’re encountering is just the effect of a scene lit mostly by emissive lighting. This is not the recommended approach for lighting entire scenes in Unreal, as the Lumen GI is just not equipped to handle track-style emissive lights. I would suggest adding in Rect lights to replace the main lighting the emissive is giving off, and fake the effect of the light coming from the emissive source. I think you will find that when the two light types are used together, your noise will be much better.
That being said, here are some controls that I found, which I think will at least help you achieve better results with Lumen’s emissive:
In your postprocess volume:
Final Gather Quality = 5
Through console commands:
r.Lumen.ScreenProbeGather.RadianceCache.ProbeResolution 64
r.Lumen.ScreenProbeGather.DownsampleFactor 4
r.Lumen.ScreenProbeGather.FullResolutionJitterWidth 4
r.Lumen.ScreenProbeGather.RadianceCache.ReprojectionRadiusScale 1
r.Lumen.ScreenProbeGather.RadianceCache.GridResolution Play around with this value, the default is 48