He everyone, I recently purchased Vue 6 Pro Studio. I'm using a MacPro with 16 gigs of memory. Despite all this RAM, my single frame scene takes over 3 hours to render using the "Final" render option, and that's not even full screen. This is frustrating because ultimately this scene is to be a 10 sec. animation. Other posts I've read imply that 4 gigs of RAM is optimal, compared to less, so why isn't 16 gigs much much better. Is there such thing as a RAM limit? Right now the scene is a single terrain, with a multilayered material. I've placing groupings of trees, rocks, and other plants manually, as the ecosystem method populate more of the landscape than I need for this shot, and I've imported a simple tipi model from Cinema 4D. There are well over 39 million polygons, this is a lot I know, but my scene doesn't seem any more complex that any of the spectacular work by other Vue artists I've seen. Thanks for any help Brian

16 gigs of ram is a lot, but does your OS support it? I don't know Mac, but windows for example in a 32bit version will only allow 2gigs of ram per running program. If you are not using the 64bit edition of Vue, you only use 2 gigs of ram. Ram isn't everything when it comes to rendering, CPU power is very important too. 
Do you have a spectral atmosphere in your scene? Do you use one of the advanced lighting models, such as GR, or GI?
There are many things you can do to help cut down rendering times.
I suggest you read this:
http://users.tns.net/~mwalter1/Vue_Render_Settings.pdf

bruno, XP Pro 32 Bit will see and use 2.93 gig of ram.   I have 4 gig right now in my 32 bit system and XP is seeing and using 2.93 of the 4 gig.
  I will add 4 more gig when I get my XP Pro 64 bit cd so I can install it on another partation. :)

Yes, but it will only allocate 2 gigs to Vue or any other app, even if it sees and makes use of 2.93
And also Vue6  32bits cannot use more than 2 gigs anyway.

bruno is correct, Pro and Esprit are 32 bit apps, and do not use memory as efficiently as does Inf and xStream.  And they can only use 2 CPU cores compared to Inf and xStream so are much slower at processing scenes than the other two apps.  Additionally, the ecosystem and layering of materials is also not as poly efficient and therefore takes additional time to render.  

Again, a low poly count does not indicate a quick render.  On the contrary I have created scenes with only 60,000 polys with two Displacement materials, that took 22 hours to render.  Catch 22!