If I may chime in with my own opinion here... :)
A good indicator for a CPU speed in terms of rendering performance is also Cinebench - that includes single threaded performance.
The numbers you get there clearly indicate that the 4790k is faster than even the 1800x. Heck, the 4790k is faster than the 6950x ... In single threaded apps that is.
Now, I think the question to be asked here is whether you really care about that? So, say you get 20fps in your viewport heavy scene (specially true for c4d) and now your new CPU is 15% slower in single threaded speed.
Effectively, you are probably leaving what, 2-5 fps on the table?
Same goes for Photoshop. That dual Xeon build on 3.2ghz max is making your lens blur be slower for X seconds... Say you need to wait 6 seconds more on a 40 second effect.
So... Are those seconds really that important compared to you rendering 2 hours instead of 4 hours? Think about IR and those quick region renders that you need asap...
In that case I'd argue that multi-core speed will probably save you more time in the end.
Of course, there is no perfect tool (=hardware) for everyone. For me, personally, I'd rather balance the scale because the work I do includes the need for fast single threaded speed too. I mean overall, its good to have a well balanced rig and again, personally, I think the Ryzen series will give you that.
To be honest, comparing something like a 1800x will pull you into heavy Xeon territory with regards to prices. Then again, if you pick up a 2699 with 3.6-3.8 ghz of single threaded speed then of course, its going to be pulling close / ahead of Ryzen in both multi-core and single thread speeds... Just for a lot more money, of course.
That is why workstations usually balance the two, to an extent (you generally don't put 2.8ghz XX-core Xeons ni your workstation - although it might work dandy for a lot of people I guess). You either take a little bit of that multi-core power to enhance the single threaded stuff... or vice versa, depending on what you prefer really.
I don't want to make this a marketing post for Ryzen so I'll conclude by saying that if you were rolling on a 4790k (or 6700k or 7700k) then good luck finding that same single threaded speed in a 20 core Xeon. Will you notice it in your workflow? That is another question... Perhaps a nvme would speed things up more depending on what you do :)
Oh and PS: If you are doing a lot of sim work, marvelous designer type of stuff... Yeah, you NEED single threaded performance! Ryzen does have very good single threaded performance - The IPC is in the Broadwell-E range afaik.
And for some numbers:
(
https://www.pugetsystems.com/labs/articles/Adobe-Photoshop-CC-2017-Intel-Core-i7-7700K-i5-7600K-Performance-879/)
Just my five cents :) Hope it helps and don't forget, everything is debatable :)
