Finally got around to trying a benchmark. I used this one, from the Poser 11 days.

https://www.renderosity.com/freestuff/items/83640/benchmark-test-scene-for-superfly

It took 20 minutes to render the scene in Poser 11, with my old computer. It was just under 14 minutes with Poser 12, also with my old computer.

With my new computer and Poser 13:

15 seconds with Optix

20 seconds with GPU

5 minutes 6 seconds with CPU