Workstation for Rhino 5 and Vray 2.0 help needed

Hi all,
we need help to renew our workstations. We actually work with Rhino 4 and vray on 4 old PC powered with i7 870 2.9 GHz, 8gb RAM and GeForce GTS 270. For our normal workflow are still good but for our “heavy” projects (4-500 Mb model files) a little bit less…
What we would like to do?

  • 3d modelling
  • smooth 3d visualization (render viewport with Vray)
  • Renders with Vray 2.0
  • I really would like to have RT renders on Vray 2.0 (GPU based render)
  • photoshop (light use)
  • 2d drawing with Microstation (but we will migrate to Autocad LT)

Now the big question is: is it worth to buy a proper workstation (Xenon and Quadro) or it’s better an i7 + dual GPU?

The budget should be below 2500-3000€.

Any help will be really appreciated…
Thank you all, ciao

Tommaso