Its the older cheese grater Mac Pro, 2012 and Cinema4D R21 and Vray runs perfectly fine on it with the current 1080 card but Cinema 4D R23 needs the system to upgrade to at least Mojave and the graphics card isn't compatible. I have viewed the new Mac Pro and would have been interested apart from the ridiculous price point and several reviews saying that it hasn't improved the speed of their workflow for several software packages including Cinema 4D, Final Cut Pro, Adobe CC and others. Some design companies who tested the new mid range Mac Pro also saying the software itself sometimes an issue as it hasn't caught up as it doesn't know how to utilise all the cores and extra Ram available so don't know what to believe, but certainly not paying £10k plus for a machine that doesn't give me considerably less render times. Hopefully in a year or so the price point may reduce to a more reasonable, affordable price at which point I would consider but for now the graphics card is the only thing slightly hampering my progress.
I have to say you are the first user Ive heard say that this older cheese grater Mac Pro hasn't still got a place in the graphic design market. The new cheese grater alienates a lot of small to medium business users at its price point and the trash can as you say a terrible machine. Sounds like you are advocating the switch to PC? Have to say I'm not sure the software runs identically on both platforms, certainly past experience would suggest there's always lots of small differences in the layout and shortcuts etc... but maybe that's changed. Maybe it's more a case of the devil I know, now that I'm heading into my twilight years as a designer.
Thanks for the feedback though.