The MSI MEG Z890 ACE is the objective winner of this comparison, securing victory in ten out of thirteen evaluated specifications. Its most significant advantage over the Gigabyte B660M DS3H DDR4 is its maximum memory capacity, which is 300% higher. While the Gigabyte B660M DS3H DDR4 holds a 100% advantage in the number of PCIe x1 slots, the MSI MEG Z890 ACE dominates the overall feature set across the majority of the measured categories.

Users requiring extensive memory support for high-demand tasks should choose the MSI MEG Z890 ACE to leverage its superior capacity. Conversely, the Gigabyte B660M DS3H DDR4 is the appropriate selection for builders who prioritize a higher count of PCIe x1 slots for their specific expansion needs. Selecting between these two motherboards depends entirely on whether your build requires the expanded memory ceiling of the MSI option or the specific slot configuration offered by the Gigabyte alternative.