That’s really interesting, from our testing with UE4 I’d expect to see the new Mac Pros a bit further ahead of the Nvidia 775, so that’s a bit surprising. The spec. lineup with the W series cards is also illuminating.
It is a bit surprising that that 's aren’t faster in the linked article, but I never said it was the most cost-effective Mac around, just that it isn’t an especially poor performer either. Like the G4 Cube the 2013 is beautiful, but at a substantial cost. The could potentially run UE4 faster still if we were able to use the second GPU efficiently but that is extremely tricky and it isn’t a priority to optimise one small subset of Macs for the moment.
As Chris.B says in the Q&A at the end, AMD don’t optimise their Mac drivers just for CAD or just for games. His team have been fixing bugs on the D-series cards for us as we’ve reported them, just as they did for the 6000-series back when I was porting Batman Arkham City .