I opened your file and it renders in 18 seconds. I have not cached my scene rigid bodies. I fail to see how that would affect the render, as it is as I said before, immediately rendering to the viewport.

Appreciate the help on this Sassi boy

Here is the link to the project file: https://www.dropbox.com/scl/fi/i1oqb6trlx0zfbeyl1ai1/FirstLights_Geraldton_V04.c4d?rlkey=nx6vr4bxck1lm3ufzhp9i4twy&st=tnmla0wi&dl=0

Its a very simple setup, there are a bunch of cloners, 8 to be exact. All with varying amount of clones of spheres with 16 subdivisions. The total number of clones/spheres in the scene from these groups is 240. They have one shader applied to all. This is using the color data connected to the emission.

Effectors are mostly inheritance to move the spheres from one cloner object to another. There are others that control colour, very simply with a shader field and box field. There are rigid bodies on each sphere, for collision spacing. Could it be this? Some sort of calculating in the background? despite it rendering immediately in viewport. This is the biggest confusion.

Have just made scene with 600 spheres, same material and colour effector. It renders immediately. More sass please or I'll throw C4D into the sea.

Creating a drone show. Basically a swarm of spheres with the effectors controlling their position and colour via the luminance channel. Simple.

Render is immediate when done to viewport. Rendering to picture viewer takes almost a minute per frame, if not more. Ive complex scenes with GI and volumetric lighting that render quicker than that. What is going on?

To reiterate. 0 lights, only the emission channel needed. I have tried this in both redshift and physical/standard renderer. All the same.