ROG Strix B550-XE Gaming ATX motherboard is PCIe® 4.0-ready and features a robust power design, comprehensive cooling controls, AI Networking and cyberpunk-inspired looks.
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Top slot is PCIe v4 and bottom one v3. M.2 with PCIe v4 will work in second slot at v3 speeds. That's how it is with most b550 MBs.