Although the new Macs have only two Thunderbolt ports, compared to four on the Intel-based 16-inch MacBook Pro and Mac mini, TenPlus has discovered that each port has its own Thunderbolt bus. By comparison, each pair of Thunderbolt ports on the Intel-based Macs share a bus, meaning that they also share bandwidth. If you plug two fast drives into ports that share a bus, performance suffers. Our engineers also note that the M1-based Macs have Thunderbolt 4, which differs from Apple’s implementation of Thunderbolt 3 in only one fundamental way: Thunderbolt 4 adds support for Thunderbolt hubs that let you add more ports.
So yes, the M1-based Macs may have only two Thunderbolt ports, but they’ll both provide full bandwidth for up to four devices through a hub. And as you might suspect, TenPlus carries a full line of Hubs and will soon have the newest Thunderbolt 4 Hubs.