Choosing DDR4 ram for a ryzen gaming build

3600MHz CL16 is the sweet spot for Ryzen on DDR4, cheap and fast enough. Two sticks, not one, so you get dual channel. 2x16GB is what I'd go for these days. The bit everyone forgets: turn on XMP (AMD boards call it DOCP or EXPO) in the BIOS after you build it. Otherwise it runs at a much lower default speed and you've paid for nothing.