A mechanism, a bridge and a case, and buyers compare the wrong one of the three
The best external hard drives for 2026
An external drive is a mechanism, a bridge chip and a case, and shoppers usually compare the wrong one of the three. What sets the speed of a desktop model is the mechanism inside, since a spinning drive cannot fill even a five-gigabit link; what sets it on a bus-powered solid-state model is the port standard at each end of the lead. Read the USB generation the maker publishes together with its rate in gigabits per second, and read the connector as a separate line, because a Type-C socket says nothing at all about the speed behind it and the cable in the box is part of what you are buying. The second division is portable against desktop. A 2.5-inch portable drive takes its power from the lead and fits a coat pocket; a 3.5-inch desktop drive wants a mains adapter, holds a great deal more, and stays where it is put. Capacity is quoted in terabytes of a thousand billion bytes, and the same drive shows a smaller figure on a machine displaying in units of 1024; this site publishes the maker's number in the maker's unit rather than recalculating it into another. Then the things that decide whether it survives a bag: the case material, any stated drop or ingress rating, and the length and type of the cable supplied. Software for scheduling copies is published by most makers, and some models describe a hardware encryption feature in their own terms. We compare capacity, portable or desktop format, USB generation and stated link rate, connector type, power source, stated dimensions and weight, cable supplied and warranty length.
By Jean-Benoit Buisson
