I am also trying to figure out i7 versus xeon choice.
Favouring cpu all depends on the workflow... not only for one program lilke ArchiCAD,
but for all important programs on that PC.
My main workflow is with ArchiCAD using OctaneRender and CorelDraw for postproduction,
My experience is that waiting for big AC scenes to load into Octane takes most time waiting and counting sheeps or get me a cup of coffee
In AC itself loading heavy floorplans takes a long time, and this is being done singlethreaded
Probably give in a little in cpu performance for some tasks (like loading the heavy floorplan)
might be worth in gaining a lot more in other tasmks by going with xeon chips with a lot more cores (and even going dual cpu).
But the single core performance of xeons in general are not that high as i7 or very expensive...
So, it is easy to stay in doubt waht the better choice is fro certain workflows.
below is from another guy from the octanerender forum and this is very informative and maybe it can make decision easier,
at least, I would take my chance and go for dual e5-2640 v4 instead of single i7.
Quote from lucky guy:
"....I will only focus on the Xeons now.(2 x 2640 v4)
Before that let me say that I also own a system with an i7 4930K OC'ed a little to 4.3Ghz.
Let me say this, If you can go with Xeons, do it. They are amazing.
In my case at the beginning I thought I would sacrifice single core performance but I was wrong.
It runs like butter through anything and it is so much faster than my i7 it's ridiculous.
It runs much cooler also, both on water, the Xeons don't reach more that 38C under full load.
The i7 goes much higher than that. So to give you some numbers,
the i7 OC'ed at 4.3GHz runs Cinebench 15 at 1074 and 144 for single core.
Now the Xeon runs the CB15 at 2691 points Multithreaded and Single at 138!
Even in single thread its very fast and at 3.4 GHz it's almost as fast as the OCed i7 at 4.3GHz!
That shows that clock for clock the Xeon runs faster, much more efficiently (at 95W) and much cooler.
Everything else also runs supersmoothly ."
When going i7 anyway I would choose 6850K (6 cores 3.6ghz /3.8 ghz turboboost)
or if you really need more cores and have some money to spend i7-6950X (10 cores, 3.0/3.5 ghz, but almost triple priced!)
It would be nice though to have an ArchiCAD user with (dual?) xeon to actually give his experience on performance for singlethread ArchiCAD tasks,
and compare with i7.
W8.1(64), AC19(5005), OctaneRender plugin, Corel, Adobe Premiere Elements 11.
Cosmos II, MSI X99S Gaming 9 AC, i7-5930K 3.5gHz, multiple GPU (1080Ti+Titans: 4Z+X+2Black), 32GB, 1500W.