I am interested to see the choice of memory, and why that is chosen. I would also like to hear why the 3950x would be much better for gaming than a thread ripper, other than it would be cheaper. (I think in the long term, CPUs with many more cores will have much longer term value.)
Also, why would you choose that case? And that PSU? (The machine would be on almost all day every day...)
You seem to reference some suggested build. Which one?
Anyway, regular Ryzen is better than Threadripper because it's cheaper. Performance doesn't differ in any significant way.
While future games will make better use of more threads that shouldn't scale straight off with the number of cores. Definitely not so much that it's a good idea to spend lots of extra money on more CPU-cores instead of a better graphics card.
The only reason for discussing 3950X vs Threadripper in a gaming rig is that you require a lot of computing power outside of gaming. Then you should go with the CPU that best fit those needs and requirements.
For a "pure" high end gaming computer I'd settle with a Ryzen 7 because Ryzen 9 is overkill. The money freed up would be used for low latency 3,800 MHz RAM.