The MSI MAG B550 TOMAHAWK is the objective winner of this comparison, securing six spec victories against the single win claimed by the Gigabyte B660M DS3H DDR4. The most impactful advantage for the MSI MAG B550 TOMAHAWK is its PCIe x16 slot configuration, which offers a 100% improvement over the alternative. This hardware superiority makes it the more robust choice for users requiring extensive expansion capabilities for their system builds.

Users who prioritize hardware connectivity and expansion should select the MSI MAG B550 TOMAHAWK for its superior slot count. Conversely, the Gigabyte B660M DS3H DDR4 is the appropriate choice for budget-conscious builders, as it holds a 44% advantage in MSRP. By choosing based on these specific strengths, buyers can align their purchase with either the need for greater component flexibility or the requirement for a more cost-effective motherboard solution.