Question MSI b450m Mortar Max vs Tomahawk Max?

They are essentially the same board but one is mATX (Mortar) and one is ATX form factor, and either will work a charm with a 6 core/6 thread processor.

There is one significant difference though: the Mortar Max comes with a 2nd M.2 socket for PCIe x4 NVME. Even though it's fed by the chipset, and therefore Gen 2, it's still way faster than any SATA SSD could be. 1 TB NVME's can be had pretty cheap now so in addition to a high-speed system drive you can also have a high-speed data drive for super fast game loads!