Regarding motherboards, there are a few primary differences between the B450 and B550 chipsets. The first difference is that the B450 has an older GEN motherboard, while the B550 chipset is designed for mid-to-high-end P.C.s. The second difference is that the B450 chipset supports PCIe 3.0 with 8GT/s, while the B550 chipset only supports PCIe 4.0 with 16GT/s.