i have 4gb and 16gb =20gb ram (i think) but 8 GB will be running in dual channel and 12 GB in single channel.
part of the cpu-z txt report
Memory Type DDR4
Memory Size 20 GBytes
Channels 2 x 64-bit
Memory Frequency 1596.7 MHz (3:48)
Memory Max Frequency 3200.0 MHz