Poser uses Opengl for its preview display but uses only the processor for rendering. If poser is choppy in preview you can change from full tracking to box tracking and from texture display to smooth shaded. [check the manual under the HELP menu for those] . Making sure you have disk space and a good amount of virtual memory will also help. You can turn on Task manager and check the committed /available memory [ctl/alt/del]
A render of a single figure with clothing and hair can take from 5 minutes to an hour depending on render settings. Even with a fast processor its not a quick process.