How we test
We put each of the drives through the same selection of tough tests to determine our winners
We use two tools to thoroughly test the performance of each drive in this month’s Labs. The first is the synthetic AS SSD benchmark, which measures raw sequential read and write speeds for each drive – giving an indication of how quickly it can load and save large files – as well as random-access 4K operations across 64 simultaneous threads, showing how it copes with heavy demand. You’ll find the results for each drive in our graphs on p92. All drives are formatted with NTFS, although if you want an external drive to be fully usable in both Windows and macOS you should choose the ExFAT file system – performance won’t be significantly different.
We also use the PCMark 10 storage benchmark suite to assess real-world performance. These tests use “traces” – captured sequences of read and write operations generated by real desktop activities – to put every drive through a standardised workload. The system drive test includes booting Windows, launching and using applications such as Adobe Photoshop and Microsoft Excel, launching Battlefield V, Call Of Duty: Black Ops 4 and Overwatch and copying data files both to and from the target disk. We also perform the data drive test, which focuses on file-copy performance. Both benchmarks produce absolute performance scores, which again you’ll find on p92.
Of course, performance isn’t the only consideration: value for money is of the greatest importance, and you’ll find a price-per-gigabyte calculation among our graphs on p93. We also look at any extra features such as hardware encryption or bundled software, and for external drives we factor in style and practicality. Based on all of these considerations, we award each product a star rating out of five.