The Gigabyte B550 AORUS PRO AC is the objective winner of this comparison, securing more individual specification victories than its competitor. Its most significant advantage over the ASRock B550 Steel Legend is the inclusion of additional PCIe x16 slots, which represents a 50% improvement in that category. While both motherboards share many identical specifications, this expansion capability gives the Gigabyte board a clear edge in overall hardware connectivity and configuration flexibility.

Users who prioritize multi-GPU setups or require extensive expansion card support should choose the Gigabyte B550 AORUS PRO AC for its superior PCIe x16 slot count. Conversely, the ASRock B550 Steel Legend is the better option for builders who need to maximize internal storage capacity, as it offers a 50% advantage in the number of available M.2 slots. Your final decision should depend on whether your build requires more storage drives or additional expansion cards.