3D Modeling used to work but is not usable! in xppro/bootcamp

Hello,

I finally got my parallels 4 working in snow leopard... but now when i use a 3d modeling program navigation in that program is so much slower then it used to be in parallels 3! The program i am using in windows is Rhinoceros 4. Before rhino 4 in parallels was usable for small to moderate files, but presently it is competely useless.


Setup:
I am running parallels 4 on my mac running snow leopard, parallels is running xp pro from my boot camp partition.