By the way, I don't find any significant difference in render times , using the same settings as before.

But then my renders were often taking such a long time before, anyway, due to scene complexity, maybe I wouldn't notice.

I'm rendering an updated version of my last "watchmaker" image just now though... that's a pretty simple scene by my standards... and it seems to be just as fast as it was before, at 4096 x 4096; i.e. about 20 mins for the IDL pre pass, with an IC value of 47-ish and shading rate of 0.4... about the same sort of time for the SSS pass.