An alleged slide disclosed by an online publication shows AMD would be aiming for DDR5 support by 2022. In doing so, it would make its way to the mainstream platforms. 

AMD would see 2022 being the target to releases and bring ddr5 to the market. It will enter the mainstream market through Zen4, but APUs would also follow the same path in that year. In addition to ddr5, support for USB4 would also see the light of day. The source posted an internal AMD roadmap, which shows that AMD will start to support DDR5 in 2022. Zen 4 processors won't be the only ones to support DDR5 in 2022. There will also be Zen 3+ APUs with DDR5 support, and laptop chips that will also support this new standard.

it is an internal roadmap though and 2022 is far away, but perhaps it'll be the year of DDR5. In the previous research and development data released by SK Hynix, the DDR5 memory speed can reach 8400Mbps (8400MHz), a single DIMM can reach 128GB while power consumption is reduced. As for USB4, it is actually a variant of Thunderbolt 3 with a speed of 40Gbps and supports charging and DP signal transmission. SK Hynix's statement is that DDR5 memory will be mass-produced this year. In this way, Intel is expected to take the lead.

DDR5 and USB 4.0 going mainstream in 2022 (according to internal roadmap AMD)