Wow. 32 posts into this thread and practically zero specific relevancy to the Mac Pro at all.
Zen doesn't look to be viable given the current baseline Mac Pro design criteria
"... This would indicate that slot three has a full x16 lane connection for data, or in effect we have 64 lanes of PCIe bandwidth in the PCIe slots. That’s about as far as we can determine here – we have seen motherboards in the past that take PCIe lanes from both CPUs, so at best we can say that in this configuration that the Naples CPU has between 32 lanes and 64 lanes for a dual processor system. ..."
http://www.anandtech.com/show/10581...-naples-32cores-dual-socket-platforms-q2-2017
1. Not getting double socket Zen any more than getting a double socket Intel offering. [ the relevant number above is the likely 32 lanes per socket. ]
2. If Zen ( desktop and server) is 32 lanes per socket. Xeon E5 v1-4 is 40 and hints that version 5 will may crank that up to 48. (e.g., multiple TB v3 (or better) controllers and dual GPU slots would stretch a single socket's bandwidth ). [ AMD is in the game but .... not at level with v4 ( Broadwell-E) in terms of I/O bandwidth. [ selection of Blender likely driven by the somewhat better job of RAM channel I/O parity and other CPU function unit improvements. ]
3. If Southbridge is in-package that may have some negative offsets in routing complexity. [ geared toward single board implementations. Not what the Mac Pro internals look like. ]
Best case is that Zen Server options means that Intel doesn't kneecap the E5 v5 so much on performance and price ( e.g., kneecapped 4 core clock/turbo or set low cost floor at 6 cores without kneecaps on I/O. ).