Source is my system and extensive testing with several coolers. First heard about it here (I think)
View: https://www.youtube.com/watch?v=g94rNe4XSGU
didn't exactly believed it at first so I experimented too and results were roughly same not counting silicone lottery.
My results with 3 consecutive runs(enough to stabilize temps) of CB r20 .
62c - 5024 (highest boost 4.382MHz one core at a time and 4.25GHz other cores
71c - 4963, 4.31Ghz best core, 4.2 other cores.
75c - 4892, 4.28GHz best core, 4.1other cores
78c -4797. 4.125GHz best core, 3.97 other cores
There are some other scores in between and at a bit higher temps but there's too many to list here.
I also had 1600x, 1700x (with XFR only) and 2700x previously. They were on x370 MB and 2933 and 3000MHz RAM so can't compare them with present system and I also lost results due to a virus at one time.
Who doesn't believe let him try himself.
PS. I never got them to throttling point, those are just frequency changes impacting PBO and test results with it. Temps checked with HWinfo64 and Ryzen Master.