The MSI MEG X870E ACE MAX is the objective winner, securing victory in ten of the thirteen compared specifications. Its most impactful advantage is a 300% increase in maximum memory capacity compared to the Gigabyte B660M DS3H DDR4. While the latter motherboard offers a 100% advantage in the number of PCIe x1 slots, the former dominates the overall technical comparison by providing significantly higher memory support and superior specifications across the majority of measured categories.

Users requiring extensive memory capacity for demanding workloads should choose the MSI MEG X870E ACE MAX for its superior memory ceiling. Conversely, the Gigabyte B660M DS3H DDR4 is the appropriate selection for builders who prioritize a higher count of PCIe x1 slots for specific expansion card configurations. Select the MSI option for high-end memory requirements or the Gigabyte alternative if your system architecture relies specifically on the availability of additional PCIe x1 connectivity.