B550 motherboards are exactly what you expect: They’re like the existing B450 mainstream Ryzen motherboards, built around the backward-compatible AM4 socket, but with support for PCIe 4.0 included.

So, rather than being a B550, or even a new release of a rebranded B450 with PCIe 4.0 support, it looks like the leaked AMD B550AM motherboard might be an old rebranded B450 with PCIe 4.0 support ...

The ASUS PRIME B550-Plus (Socket AM4) AMD B550 ATX DDR4 Motherboard delivers high-performance computing with support for AMD Ryzen processors. It includes dual M.2 slots, PCIe 4.0 support, and ...

The MSI B550 motherboard supports the 3rd Gen AMD Ryzen processors with the addition of PCIe 4.0 technology for eye watering speeds. Introducing the all new B550-A PRO Motherboard from MSI.

There's no definite guarantee that these boards will be PCIe 4.0, but considering a B550A chipset has already been seen in previous (OEM-only) motherboards, it would be a bit silly for them not to be.

PCIe 4 made its debut with AMD’s third-generation Ryzen processors on its 500-series motherboards, specifically with the x570 chipset. As of early 2020, the only motherboards that support PCIe 4 ...

Much like some of the other best motherboards on the market, the ASRock B550 has all the modern expectations of a gaming motherboard, such as two M.2 slots and one PCI Express 4.0 x16, which you ...

Especially as PCIe 4.0 and PCIe 5.0 slots become the norm. Plus, ... You can still get up to speed on a budget with Gigabyte’s B550 Gaming X motherboard.

Lack of total PCIe lanes is one of the biggest problems with current-gen chips, IMO. AMD is very careful not to include this on their spec sheet, but IIRC, the 5600G devotes 8 lanes to the ...