Quote - I would NOT recommend XP64, it's very unsupported and problematical versus Vista 64 bit.

See CS4 Photoshop vs XP64, yet it's fine on my Vista rig (just got CS4 Extended...grr, adobe EUrope prices!!!, but awesome app).

Silverblade, what's the issue with XP64?  There are many more users using XP64 than Vista 64.  The testing I've seen with the Vuemark benchmark shows that XP64 is about 15% faster than Vista 64. 

Quote - Vue can use up to 2gigs, which is the max Windows 32bit allows per application. Displacemnt can be tricky, not only in Vue, I've add OOMs in Cinema4D using displacement. Some fractal nodes are very demanding, even some of the "simple" fractals ( as opposed to variable roughness and 3noises fractals) , like voronoi, round samples and square blobs. Vue can be caught in an endless loop trying to compute the resulting geometry while at the same time trying not to crash, which is why I think memory usage goes to 1500 then goes down a bit, and goes up again. It is trying to free some memory (or maybe it is windows doing this), and loses some information, then recomputing wha's just been lost, etc....

Bruno is absolutely right on the displacement stuff.  It doesn't take much to cause OOM errors on 32-bit platfroms.  I have similar problems with MudBox on 32-bit.  I've never had an OOM crash on XP64