How we test hard drives

A person holding a stopwatch

We timed how long it took to transfer data between the hard drive and our computer

Ease of use

Hard drives aren't exactly the most complex bits of machinery we test but, nevertheless, it can still be a real pain if you end up with the wrong one. It's not just the speed of data transfer that can make the difference between a good and bad drive, niggly things like too short leads or poorly positioned buttons can end up becoming a real irritation.

We set up and install each of the drives as a typical person would. For example, we measure the length of the accompanying leads. If they're particularly short they'll limit where you can position your drive. We rate the location of any buttons (the on/off switch, for example) on the drive, too, in case they're awkwardly placed or difficult to identify.

We also scrutinise any manuals that come with the drives either on paper or preloaded on CDs and assess them for how clear and complete they are.


Our experts load any software that needs to be installed, then transfer large files and small files across to the external hard drives and time how long each transfer takes.

We then try to access the files held on the external hard disk on our computer and, once again, time how long it takes for each set of files to transfer back to our powerful test computer.

Drives get marked down if they are noisy, get too hot or if they guzzle power – especially when they are just idling. We assess them for practical things like whether they have power lights, and lights that illuminate to show they are actually doing something.


For the portable drives, we assess them for robustness, how much they weigh and how easy they are to carry around.

Cookies at Which? We use cookies to help improve our sites. If you continue, we'll assume that you're happy to accept our cookies. Find out more about cookies