I have a 2x kit of HX434C19FB2K2/16 for 4x8Gb which I bought in the beginnings of 2018. Has Micron E-die 16nm
I got them to stable 3733Mhz with my Ryzen 7 1700 and a Gigabyte AB350-Gaming 3 when Agesa PinnaclePi 1.0.0.6 hit the board. Before that I was limited to 3600Cl14 stable.
I later changed my motherboard as I was limited by SoC voltage to run higher speeds on that gen 1 Ryzen. Sadly the later board is capped to 3200Mhz, a Biostar x470GT8 as it currently stands. I'm just waiting if new BIOS will unlock this board or if it's a hardware limit.
Not tested newer bios on the Gigabyte if they allowed even better results as I don't want to dismantle my current setup.