Bill, quick question: when you measure render time, do you start the clock after all the textures have finished loading and the shadow-maps have been generated and all that? Because if you'd already had the base colourMaps loaded into memory from before, your shader doesn't cost that much time, does it? It never did me...

Monterey/Mint21.x/Win10 - Blender3.x - PP11.3(cm) - Musescore3.6.2

Wir sind gewohnt, daß die Menschen verhöhnen was sie nicht verstehen
[it is clear that humans have contempt for that which they do not understand] 

Metaphor of Chooks