How we test external computer storage

How we sort the good from the bad in various types of storage drives for your computer and mobile devices.

Portable, NAS, desktop, and wireless external drives

Whether you're using a desktop computer, laptop, tablet or smartphone, chances are you'll eventually need extra storage, usually external. This can range from a network drive to a desktop drive, pocket-sized portable drive, USB stick, or just a thumbnail-sized memory card.

There are many similarities in the way we test these different forms of storage, but also key differences in our test methods across categories to take into account their special features. This article explains how we look at each category and the approaches we take to test and assess them.

In this article:

See our latest test results and reviews of portable storage drives, NAS drives, external desktop drives and online storage.

Our expert testers

Storage is one of the most important parts of any computer system, which are also often the hub of a whole range of other technologies. There's scanning, networking, display screens, accessories, lounge room media players and all kinds of software, from operating systems to productivity programs, backup, cloud services and more.

Our expert computer testers have extensive experience in working with a wide range of consumer-level computer-related technologies, because it's not just about how the computer works but also how it fits into your home technology ecosystem.

How we choose what we test

More than any other category of household product, computer technology is constantly updating and evolving, and that goes for storage as well. The pace of changing technology means we constantly have to re-evaluate how we store our computer files. Storage drives are on a constant journey to faster, smarter, higher capacity while at the same time becoming cheaper. Computer improvements come so thick and fast that it can be just a few short months before newer and better models hit the market, but external storage can outlive your computer and migrate from one machine to another.

We start by doing extensive market research to find the right models to compare and we aim to include models in each category from across all the major brands. This includes talking directly with manufacturers to find out which models will still be available on retail shelves by the time testing is completed and the results published.

We also we try to establish a level playing field for testing across a category, though the variation in the range of options available can make this a real challenge. It's worth noting that there are often several models of a particular storage drive available, varying in capacity and price and sometimes in features and even colour options.

Despite these limitations, the models tested should give you a good indication of how a particular model family rates against current competitors, including the advantages and disadvantages of its overall design and any special features and inclusions.

We look to include the most up-to-date and popular models available in the big name retail outlets, and buy them off the shelf or online just as you would. This way you can be sure that what we test is the same as what you can buy, and that our results should be what you can expect for yourself.

The types of storage drives tested include portable hard drives, solid-state drives, USB thumb drives, NAS (network attached storage) and external desktop hard drives.


Some specifics of how we test vary depending on the type of storage device on test. However, all testing includes comparisons of performance and ease of use.


This is tested by transferring sets of data to and from each storage device multiple times. We time the transfers, noting both the read and write speeds to measure the drive's performance, averaging the speeds for a final figure. We use separate sets made up of large files and of small files.

Ease of use

We also compare the ease of use of each storage drive and any software supplied, taking into account the time to get set up, intuitiveness of the user interface, and how easy it is to do common tasks with the software.

Power consumption

We measure power consumption for all devices in active use and on standby, calculating an annual cost based on an average use scenario applicable for that category using current rates.


We apply the following interpretation to the scores achieved in our tests. When we describe a result as "excellent", "poor" etc, it usually relates directly to a numerical score in that range.

  • 0–24 Very poor
  • 25–45 Poor
  • 46–54 Borderline
  • 55–69 OK
  • 70–79 Good
  • 80–89 Very good
  • 90–100 Excellent

Ready to buy?

Take a look at our latest test results and reviews for computer storage including:

Or, if you're still researching, read our buying guides: