Hi and thanks for the answer.

With PE Explorer you can force Poser to use more than 3 GB. When I render my stuff, just like this -> http://rhian-skyblade.deviantart.com/art/Having-a-chat-at-the-tavern-77009738 and my Perfomance-Monitor tells me that 3,75 - 3,8 are in use during the process. Nothing else beside Poser runs during that time.

(I do not dare to show my stuff here yet, until I am good enough :D )

This took nearly 1 hour of rendering.

The Background you see there belongs to the Medieval Tavern, and I used the Tap-Room / Bar Preset. It contains tables/chairs which you can't see and bottles, a bar, and a keg, and all such things. Nothing fancy with ray tracing... the only item I used ray-tracing for were the glasses/spectacles.