Last month specification sheets of two OEM systems from HP revealed that the AMD B550A chipset does not have PCI Express 4.0 support. This resulted in headlines that AMD may keep PCI Express 4.0 exclusive to the high-end X570 chipset -- but now some comments from AMD Senior Technical Marketing manager Robert Hallock indicate the regular B550 chipset may have PCI Express 4.0 support after all.
In a Reddit discussion about a Best Buy system with an ASRock B550A motherboard, Hallock specifically pointed out that this board uses a PCI Express 3.0 "Promontory-LP" (e.g. X470, B450) chipset specifically for use in pre-built systems (e.g. OEM customers). His comment suggests there's still hope for PCI Express 4.0 for the mainstream market.
No, it has a B550A motherboard. This is a version of the PCIe Gen 3 "Promontory-LP" (e.g. X470, B450) chipset specifically for use in pre-built systems (e.g. OEM customers).
OEMs are customers, too, and they may have different needs and wants than a DIYer. Not every product decision is considered through the lens of a channel product.