So, if you're buying a Ryzen CPU and thinking "WTF why is my AIO cooler not AM4 compatible?" it looks like you can blame AMD as they didn't bother to inform the company Asetek, that makes almost every AIO on the planet, the specifications for AM4 and don't even have an official spec for water coolers.

https://www.youtube.com/watch?v=705YHr1DyMw

/facepalm