A 64 bit processor and operating system will improve total throughput because of better memory management. Any quad core processor will be better than a dual core or single cpu for a multithreaded application. The graphics card does nothing for Poser except for Opengl preview, but you want to consider if you play games.  A dual video card and dual monitors allows you to spread out the preview windows , parameter dials and libraries which can mean less moving of things while working.