I like it a lot, really nice terrain! And congratulations on a paid job like this. Earth in a million years?
Even for such a processor it's a long render indeed. Probably because of the extreme displacements. PT? But don't forget any reflections. Even if a non-RT is used and it's impact is negligable, it takes so much more time.
I had one in a Roman render the other day, with some non-RT wetness in sand/gravel. Went very slow in PT. So halfway I paused it, disabled the reflective shader, and continued rendering. Went very fast after that and there's no difference to be seen in the render.
I think it would be handy to have another way of doing this in sand/gravel, get some fake shine or bluish sheen on certain angles, without TG needing to calculate real reflections. Perhaps just color and distort by normal, or so.
