The faster ram thing affects all computers fella. Eurogamer did an article on the 2500k forever ago where they showed the difference between 1600mhz and 2133 ram (the max Sandy can do IIRC?). Back then the upgrade was cheap AF as well, about £50 or something silly like that for 16gb DDR3 2133. Sadly it's rocketed since then
But yeah, on CERTAIN games (note the emphasis) ram speed makes an enormous difference. Up to around 30% in some cases !
However, that's not on all games. It seems that some of the newer ones must be coded to actually do a lot more with the ram than older games (larger textures maybe? maybe the physical ram is caching?) and they zip along with better ram.
I'm still running bog standard DDR4. Of course, as soon as I decided to buy my DDR4 rig it shot up in value and hasn't come down since. So I really can't be bothered adding faster ram.
It's the same with Ryzen too. AMD hobbled their chips on release and that's why there seem to be so many "unsure" people kicking around. Which was kinda stupid IMO. They should have delayed release and sorted the issues first.
I know from my own testing that gaming performance gets to a certain point in GHZ and then it starts to slope off. So even if Ryzen can only do 4ghz with the correct ram they should still be formidable gaming CPUs.