The ASRock B850 Steel Legend WiFi is the objective winner of this comparison, securing more victories across the evaluated technical specifications. Its most significant advantage is the inclusion of double the PCIe x16 slots compared to the alternative, representing a 100% improvement in this category. This hardware configuration provides a clear lead in expansion capacity for users prioritizing primary slot availability over other connectivity options.

Choose the ASRock B850 Steel Legend WiFi if your build requires multiple high-bandwidth expansion cards, as it offers superior PCIe x16 slot density. Conversely, select the MSI PRO B850M-A WIFI if your specific system requirements favor a higher count of PCIe x1 slots, where it maintains a 100% advantage. Your final decision should depend entirely on whether your peripheral setup relies more heavily on primary x16 lanes or secondary x1 connectivity.