So, Peter ?
You proved it's possible to grade on something else than a macpro not that it's recommandable.
I think the Biscardi man is right, If you want to colorgrade a video it's likely that you're better of with a macpro (four core, good graphicscard for instance) even when you're grading on the road in your
18 % grey painted trailer with automatic window blinds.
Let that be clear.
René A. Hazekamp (amateur colorist)
Portfolio
http://www.renehazekamp.com