Sorry but that’s not the case.
Most people it happened to did not overclock their CPU at all.
What they did was use EXPO profiles.
Here is how AMD defines it on their marketing material:
AMD EXPO™ technology is a transparent and user-friendly approach to memory profiles (see here).
Technically, using EXPO, just like XMP on Intel means overclocking the memory, albeit with parameters that underwent testing in partnership with all actors involved (AMD/Intel with Asus/MSI and Kingston/Gskill, etc…).