AMD is apparently planning another chipset for Ryzen 3000. The X590 chipset is supposed to place itself above X570 and probably offers more PCIe 4.0 lanes.
Ryzen 3000 in combination with the X570 chipset also supports PCIe 4.0. B550 and A520 for beginner boards can only support PCIe 3.0 and come from ASMedia.
AMD has confirmed that there is no PCIe 4.0 for old motherboards. In the run-up there were hints that X470 and B450 with Ryzen 3000-CPU can handle PCIe 4.0.
