Dirt cheap Gigabyte B450 S2H is surprisingly capable of 3800 MHz RAM at 1900 FCLK (even official site only lists DDR4 3600 as a maximum supported frequency) : r/overclocking
Ryzen 5 2600X vs Ryzen 5 3600 - Any Difference? - YouTube
What is the maximum RAM (size) and its frequency (speed) supported with Ryzen 5 2600? - Quora
AMD Ryzen 5 2600X – the CPU that does all the work for you | KitGuru