Very interesting, Cageman.
So I tried changing Polygon Intersection Mode from Watertight to Fastest to see the impact of the setting in a fairly slower machine.
Here it is:
PIM set to Fastest: LW_B747_Bench.lws 20m 36s
PIM set to Watertight: LW_B747_Bench.lws 22m 11s
So indeed that was quite substantial.
Renders done with LW 2020.0.1 on an i7-5960X 8C/16T OC to 4.2GHz
View attachment 148296
View attachment 148297
Wow... that is way more than my machine shows... Which scene did you render? The regular or the Volumetric one? Almost 2 minutes difference with that simple setting... wow.