AMD has announced that the new Agesa update for AM4 motherboards introduces support for memory speeds up to DDR4-4000. The update with version number 22.214.171.124 should be incorporated into bios updates by motherboard manufacturers before the end of June.
Currently, most AM4 motherboards for the AMD Ryzen processors do not support faster memory than ddr4-3200. In addition, overclockers or users of fast memory have little freedom in setting the speed, because between ddr4-1866 and ddr4-3200 this can only be done in steps of 266MT/s. With the new Agesa update that will change and smaller steps of 133MT/s can be used between ddr4-2667 and ddr4-4000.
In addition, the update adds 26 new parameters for setting memory timings. As a result, many more memory modules must become compatible with AM4 motherboards and there are more options for overclockers. AMD does make it clear that the official supported maximum memory speed remains ddr4-2667. All higher speeds involve overclocking. However, if you use memory modules that the manufacturer says are suitable for running at high speeds, this should not cause any problems.
AMD says the Agesa update has already been sent to the motherboard makers. Bios updates are expected from mid-June. Asus and Gigabyte have already released beta versions of a bios with the updates, respectively for the Crosshair VI and the GA-AX370-Gaming 5.