External drives are a part of everyday life, and the ubiquitous USB 2 connection is an effortless way to add storage. Sadly, it’s nowhere near fast enough to realise the full performance potential of a typical hard disk.
The read and write speeds you’ll see from a USB 2 external drive are normally only a fraction of what the spinning platters inside the unit are capable of.
The solution? A faster interface. The recent USB 3 standard brings a new SuperSpeed mode that’s ten times as fast as USB 2, allowing hard disks to operate at full speed. If your system doesn’t already have USB 3 ports, you can easily add them: desktop systems can be upgraded with a PCI Express card, while laptops need a USB 3 ExpressCard adapter (these cost around $50). The new standard is backwards compatible, so you can also plug a USB 3 drive into a USB 2 socket should you need to.
This month, we’ve rounded up 10 USB 3 drives to find out which models make the most of the SuperSpeed interface. Some are high-performance desktop drives, designed as a permanent addition to your workspace. Some are stylish portables that you can easily throw in a bag or move between PCs.
For both types of drive we focus on high-capacity models of 500GB or more, because it’s large libraries of data that will benefit most from a faster connection. And we also consider the important issues of design and price. Read on for our verdict on 10 of the biggest, fastest disks in the business.External hard disks are simple devices, but there are a few important things to consider if you want to get the most for your money. The 10 external drives here use the new USB 3 connection to enable high-speed transfers. Half are portable devices that draw power from the USB bus, while the rest are larger mains-powered drives, designed to sit permanently on your desk. We’ve awarded each drive a score out of six for Performance, Features & Design and Value for Money, as well as an Overall score.
In theory, USB 3 allows external hard disks to transfer data at a rate of hundreds of megabytes per second. However, in actual use this isn’t what you’ll normally see. The limiting factor is the physical disk inside each unit: some models are faster than others, and the compact drives used in portable devices are almost always slower than the larger desktop drives.
We use simple, real-world file-copying tests to measure the performance of each drive. Each drive is connected via USB 3 to a standard PC system based on an Intel Core i7-920 CPU.
We then time how long it takes to read and write a large 1.5GB file to and from the external disk, using a RAM disk on the host system to ensure the local hard disk doesn’t interfere with the results. The test is repeated several times, and you’ll see the results, expressed in megabytes per second (MB/sec), on the right. A strong performance in this test indicates a drive will be quick to read and write large files of any sort, such as high-definition movie files or ISO images.
Then we turn to our small-file tests. Creating and accessing files is much more taxing than simply streaming data, and to really stretch each drive we read and write a folder containing 12,000 small files, totalling 1.2GB, from a RAM disk to the external drive. Again, we time each drive; you can see the results in the middle graph.
The results are again expressed in megabytes per second, but really this test is as much a measure of how quickly a drive can create and access files as its ability to read and write data. Drives that do well in this test will be faster at operations involving large numbers of files, such as backing up a hard disk.
Our tests are all carried out using the NTFS file system. Some drives (as noted in the feature table below) are supplied in FAT32 format, which has the benefit of being accessible to Mac and Linux systems. However, FAT32 has a far greater performance overhead in our small-file tests: it takes roughly three times as long to write the files to a drive formatted as FAT32 as it does to the same drive formatted with NTFS.
At the bottom of each graph you’ll also see figures for a typical USB 2 drive, derived from our last roundup of USB 2 drives. All USB 3 drives are backwards-compatible with USB 2; in all cases, you can expect to see performance similar to this if you connect one of these drives via the older interface.
Based on these results, we award each drive a Performance rating out of six. Note that this score applies only to the precise model reviewed: many drives are available in larger or smaller capacities than the one we tested, and these models may achieve better or worse performance.
Features & Design
The Features & Design rating is based on a series of criteria, depending on the intended role of the drive in question. For desktop devices, we’re looking for a design that will sit comfortably on your desk without being obtrusive. Features such as a power switch and a Kensington lock slot are noted.
Portable devices tend to be more perfunctory and sacrifice features in favour of small size and portability. Here, we consider whether a drive has an access light and how easily it will fit into a pocket. For all types of drive we also consider aesthetics and any bundled software.
Value for Money
Our Value for Money score reflects the street price of each drive, but top marks don’t necessarily go to the cheapest contender. We calculate the value of each drive in terms of cents per gigabyte (see third graph, left), and then factor in each unit’s scores for Performance and Features & Design to arrive at a final rating.
Finally, our Overall rating represents the average of the other three scores, although due to rounding it may be higher or lower than expected.