Just out of interest Zanzo, what does it look like with higher Pixel Samples = 7, Shading Rate=0.4, IDL Bounces=12, IDL Irradiance Cache=20?

Those are my standard settings... oh yeah, with IDL samples=200. I don't tend to find I need to increase IDL IC past 32.

I get pretty fast renders at those settings, in a simpler scene at least, and not too much in the way of blotchies.

My render times tend to go through the roof because of scene complexity I think. Hence I do try to stick to low IDL IC.

But, my lighting will play a part in that too... I suspect that I tend to override the IDL occlusion with ray traced shadows from the low intensity Point lights I use alongside any emitters...