The benefit of more RAM is that you can render more complex scenes, at higher quality settings, and at larger pixel dimensions.  Rendering slows down as you approach your machine's RAM limit, so a machine with more RAM will render the same scene significantly faster.

     How much memory you can use will depend on which version of Poser you have (P8 or PP2010?), your operating system (32bit or 64bit?), and your motherboard.

     If your operating system is 32bit, it will only allocate about 2Gb to any given "process".  If you have Poser 5 through Poser 8, you are limited to a 32bit memory allocation -because your version of Poser is 32bit- even if your computer is 64bit.

     If you have Poser Pro 2010 on a 64bit system, it can use as much RAM as your motherboard will hold/read.  12Gb would suffice for anything but extremely complex/large scenes.  I was able to get PP2010 to draw almost 48Gb, but that was with a "torture test" scene, very complex, and using IDL with 7 or 8 raytrace bounces.

     @Victoria_Lee:  Vue will very much appreciate more RAM, and not only will you see the benefit in rendering, but Vue will also display a much better preview during scene setup.

     @ErickL88:  The core i7 is a HyperThreaded quad;  set Poser to render 8 threads with this processor.  ^^

     Laptop Pixie has a core 2 proc with 8Gb of RAM.  Desktop Galadriel has a core i7 quad and 12Gb of RAM.  Cameron has dual hex processors with 96Gb of RAM.

Poser 12, in feet.  

OSes:  Win7Prox64, Win7Ultx64

Silo Pro 2.5.6 64bit, Vue Infinite 2014.7, Genetica 4.0 Studio, UV Mapper Pro, UV Layout Pro, PhotoImpact X3, GIF Animator 5