Fairly close, really. The other major factor that's going to come into play is the Virtual memory buffer or swapfile. There are a bunch of related factors, but basically the bulk of 3D software rendering engines that are not tied to a specific card are going to be software based, and therefore entirely CPU dependent on performance. This is true not only of poser, but of the bulk of high end rendering applications as well. Modelling and the actual scene setup and design are most heavily influenced by RAM and Swapfile. CPU is then utilized for preview display, unless the display is hardware based (eg, OpenGL), in which case it's often shunted to the video card. Poser is entirely software based itself. So CPU will affect rendering and display of what you load primarily, while RAM and swapfile will handle the actual loading and adjusment tasks. Those three factors are the most important ones to Poser.

thou and I, my friend, can, in the most flunkey world, make, each of us, one non-flunkey, one hero, if we like: that will be two heroes to begin with. (Carlyle)