The MSI MAG B550 TOMAHAWK wins in 6 out of 13 comparable specs, with 5 ties. Its biggest advantage is SATA Ports (200% better).
B850I AORUS PRO wins in 2 specs (Max Memory Speed: 69% better).
Recommendation
Choose MAG B550 TOMAHAWK if you want the best overall performance — especially sata ports.
Choose B850I AORUS PRO if max memory speed matters more to you.
