I am on X570 Aorus Pro , 3950x 360mm TT AIO and 64gb ram running 3000mhz.
So I tried turning off both PBO and XFR and compared the frequencies I see in HWinfo and Cinebench 20 score.
I am now seeing three cores hitting near 4,6 and rest of them near 4,4 and 4,3 when doing light tasks or idle in Windows.
With the settings enable I never saw anywhere near these numbers, only a single core was reaching barely 4,4.
Also any default PBO settings give no noticeable difference for Cinebench score, all within margin of error. Only when I punch in custom values I see some improvement but only 300 at best which is still unnoticeable I bet.
This, plus the fact that the machine is running more than 10 degrees cooler.
As it was stated before here, even with high end cooling, I really think no reason to touch those settings