Two two-letter words can cover a multitude of performance sins. Up to almost invariably sets a target that can never be achieved, and one spec’s up to may be very different from another. I’m thinking here of Thunderbolt and USB4, both of which claim up to 40 Gb/s, but fail to achieve it in different ways, and with different types of Mac. To understand this, we need to read the fine print with care. Different Macs Look at the fine print in Apple’s specifications for its original Mac mini M1. It h...