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
Timetec Pinnacle Konduit RGB 32GB KIT(2x16GB) DDR4 3600MHz PC4-28800 CL18-22-22-42 XMP2.0 Overclocking 1.35V Dual Rank Compatible for AMD and Intel Desktop Gaming PC Memory Module RAM - White at Amazon.com
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