I made a greyscale bump map and converted it into a normal bump one. This is a render from Poser 6 SR3.  I took the cubes and low poly spheres from props primitives library. On the left is an example of displacement with that bump map. In the middle they are with the bump map in the bump channel. On the right there is normal map applied to the gradient bump channel. 

  The displacement alters the geometry. So strong that it exploded the box. Bump and displacement always have artifacts, even with higher displacement bounds in render settings.  Normal map gives high detail, but it would not show this detail from the side view in the same way like displacement does.

 Anyway, that would be great to see that real time shading in the preview window of the next Poser.