@JViz, thanks!
@Sangthorn,
Well, to each his own of course! I personally prefer rolling with more power in a single box plus Cinema 4D is quite a lot more picky when it comes to single core speeds. Based on my experience, I think there is a somewhat noticeable difference between my 2696v3s (3.8 single core) and the 4790k (4.4 single core) when working in the viewport. 3ds Max is way less sensitive about that from my experience. In that sense, I can only imagine being on a 3.0 workstation would be even weirder for everyday use.
Now with that said, I do think there is a point to be made for multi-core performance triumphing single core viewport speeds, even in C4D. That is why I kind of like to stay above 3.4 on single core turbos and get as much multi-core performance as possible.
That also goes back to the 1 CPU > 3 CPUs. Interactive rendering, which I am sure everyone uses, will be a lot faster if your rendering speed is concentrated in one box. In that sense, waiting 5 seconds less to get a usable result in the IR outweights the viewport speed decrease in my book. Unless you are running a 2ghz CPU and C4D just quits on you with a simple interior :)
So long story short, to each his own but I would go for the 2950x. Just faster workflow overall. You can buy refurbished workstations (just don't buy proprieatary ones with custom motherboards and PSUs you can't replace) later when you get more money :)
