apple has also been selling quad G5 computers for quite a while. I dunno of any inherent advantage (other than heating one's room in winter, or in summer for that matter), nor do I know if any 3D software can use all 4. however, it's the norm nowadays for OS X software writers to exclude older machines and older OS (9.x, 10.1, 10.2 e.g.). in any case, poser 7 won't be able to use 4 processors AFAIK, and there isn't even any hint yet that it can use dual processors.