King Dranzer :
At present Intel i9-7900X is best for 4K Video Editing as well as gaming. Even-though Threadripper has more cores there is no performance gain of it and in-fact performs slowly in some areas if you are using Adobe Premier Pro or the Coral Studio or SONY Vegas. Even in AE it is outperforming AMD counterparts.
But then you get into that whole thermal issue thing which Intel has and Threadripper doesn't. If you're going to be leaving your PC on doing some hardcore video editing, I'd go for the CPU that does not have the thermal issues.
So that he has headroom to add another 64GB RAM in future as per the requirement.
But how much RAM do you really need for video editing? Unless you're setting up a RAM disk (which itself requires an always on PSU) then having more than 64GB is kind of irrelevant.