RAM
Random Access Memory is what the computer uses as fast short-term storage. Instead of access the computer's long-term storage such as the hard drive, the compputer stores recently accessed programs and files in RAM. The more capacity of RAM and the higher speeds ensures that more short-term storage can be accessed in a quicker more efficent manner.
DDR4 Speeds
1600 MHz | 1866 MHz | 2133 MHz | 2400 MHz | 2666 MHz | 2933 MHz | 3200 MHz
Compatibility
The main compatibility issues were first made known with the launch of Ryzen 1st generation, released early to mid 2017. The support for RAM, CPU, and Motherboard combinations have increased but it is still wise to check compatibility on PC Part Picker or check out AMD's motherboard support list Here.