Dual CPU Xeon seems better (mmm, ECC), although faster RAM is nice, and I'm not sure what a "good" workstation board is. Is there a market for ~silent/water cooled 2P Xeon workstations still? No need to overclock, but something quiet is nice -- big diameter fans at minimum.
I have one machine with ECC, because it runs a backup server for all of my devices (Bacula, for anyone curious). I wouldn't mind it on all my desktop, though, and will probably have it in the next build. I remember asking around about the miniITX motherboard for the backup machine, just to double-check that worked with ECC before buying, and I couldn't get a simple yes/no answer out of anyone. Just a lot of words about how much I definitely didn't need ECC.
Option B is just getting two boxes and multiple inputs on monitor/kvm/etc.
Why did they come out with another Broadwell based processor when Skylake / Ice Lake seems to be logical next tstep?
This chip isn't designed for consumer workloads, so you wouldn't see much improvement if it was in your iMac, but is a nice improvement over the previous Haswell -E platform.
While it may seem on the surface that compared to the non-E version they just added a couple more cores. But the changes go deeper, for example the Broadwell-E i7-6850K has almost doubled the amount of cache, doubled the max memory to 128 GB. But more significantly, for some workloads they doubled the number of memory controllers from 2 to 4 and increased the number of on chip PCIe lanes from 16 to 40. This increase in memory bandwidth and PCIe lanes allows for the creation of monster multiGPU data processing computers.
Here is a comparision between your iMac's CPU and the new Broadwell-E i7-6850K. As you can see it is really an Apple and Oranges comparison: http://ark.intel.com/compare/94188,88195
That's even more than the Broadwell-EP Xeon equivalent:
> The recently released Xeon Broadwell-EP processor list includes the Xeon E5-2640 v4: a 10-core 2.4 GHz/3.4 GHz part that runs at 90W, and is priced at $939, which compares favorably to the i7-6950X and its 10-cores at a 3.0 GHz/3.5 GHz clockspeeds.
Those are more like ALUs, and very simple ones at that, than cores.
There are no new instructions in Boardwell-E. It doesn't support AVX512, and AVX2/1 are both part of stock Boardwell and Haskell.
The new MPX extensions are only in Skylake as well. Furthermore MPX isn't designed to increase compute, but help make bounds checking faster.
They're shifting to three phase: process(tick)-architecture(tock)-optimization.
