It does not sound like you have a good grasp on what should be running on the Master or the Slave computer, what processing power you need for either, or what computers you should be using. I strongly recommend you consult the software maker for their recommendations before spending the very large amounts of money needed to pull this off.
The Mac Pro is an expensive dual-graphics beast, that can also run a large RAM memory, but its claim to fame (and the reason for its extreme cost) is that in manages to tightly integrate a large Xeon Processor with two high-end graphics cards (one reserved for Graphics-computing only) and error-correcting RAM, and still manages to power and cool the while business adequately.
You may be better served by a PC with a mundane desktop-class processor, pathetic graphics, and a very large RAM.