iMacIntel2CoreDuo10.5.8/Poser8SR1

Especially with more complex compositions I've found that if just before I render I switch the preview mode to Mesh or Outline, for example, that Poser8 switches back from the Render window to the Preview window quite quickly... though I will say even in the Full Texture view ( or whatever its called) I haven't had as much of a wait as you are reporting.

" Try and be nice to people, avoid eating fat, read a good book every now and then, get some walking in, and try and live together in peace and harmony with people of all creeds and nations."
-Monty Python