It's actually a quite well and widely documented phenomenon. Loads of users on forums and even some of the youtube hardware reviewers have noticed it.
Even when the avg frames are slightly lower (so long as they're sufficiently high enough), many ryzen users who switched from intel speak of games feeling smother.
It's definitely true for me too.
It has something to do with the spread of frame rates across minimum/average/maximum and the consistency of frame times. Also to do with the number of cores taking care of background tasks.
Whatever it is, the gaming experience on RyZen especially when well tuned with fast, tight timing RAM, is generally spectacular.