1: 3950x isn't out that long. so way less people have done more testing then just bench marking it.
2: I expect less people will benchmark/make videos about the best memory.
the memory + cpu comparisons with zen2 launch was mainly because zen2 was completely new.
and previous zen and zen+ had some issues with certain memories.
3: unless budget isn't an issue/you plan do to other heavy tasks as well. isn't a 3950x a bit overkill for just gaming?
16cores,32 threads. and most games use 4, some 8 probably
using the 3950x is mainly for bragging rights or when budget is no argument.
as you better pair that 800dollar processor with a rtx2080ti, m.2 storage and the best cooling/coolest looking case ever.
so you're either building a pc of 4000+ dollars. or you're wasting money getting a processor you won't fully need whilst not getting the GPU/memory/storage you might fully need.
the assumption currently( do note this is an assumption) is that the 3950x compatibility with memory will be similar to all other 3rd gen ryzen..
so basically: if someone tested say with a 3900x and 3600mhz ddr4 and found it worked great. then it should also apply for the 3950x.
If I recall the sweet spots for 3600-3900 cpu are usually 3200mhz, 3600mhz, 3733mhz (with various timings)
sidenote: some reviews/benchmarks currently out now might use 3600mhz ram in their setup to test. It's the closes you are going to get to an answer.
for example:
https://www.pcmag.com/review/371925/amd-ryzen-9-3950x uses 3600mhz ram in their review
