This is the Poser 11 test scene available at Sharecg. The first render is Poser 11. On my humble GTX1060 it took 34 minutes 7 seconds.

This is the same scene in Poser 12. Render time 29 minutes 23 seconds. However note the failure of the displacement on the textures on the chairs. There are other differences due to the superfly nodes not working as before. That may account for the time difference. Also I think this may have automatically included the default post effects.

Well I wasnt going to wait half an hour so in applying adaptive sampling I set the sampling threshold to .01 (which would be high in cycles). Render time only 3 minutes 21 seconds. There is not a lot of difference.

The other thing I've noticed is that Poser 12 renders seem to be lighter on default requiring additional contrast adjustment. I like the new speed on renders, but until you guys come up with new shaders, Poser 12 is not usable for me. Wasn't there supposed to be a new material management system ?