What are the recommended memory configurations for my ROG STRIX B450-F GAMING motherboard?

You can install 2 GB, 4 GB, 8 GB, or 16 GB unbuffered and non-ECC DDR4 DIMMs into the four (4) available DDR4 slots. The system maps total size of lower-channel memory for dual-channel operation; any excess from a higher-sized channel is used as single-channel. Ensure compatibility with same version data code (D/C) modules from the same vendor. (Page 5)