Group test: USB 3 hard disks

Desktop drives analysis

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The figures in this graph show how each desktop drive performed in our real-world file-copy tests. This month, we’ve found large-file performance to be almost identical in both directions, so we’ve combined read and write speeds into a single figure.

For the small-file test, average speeds are given for both read and write performance (slower speeds represent write results). Our reviews of desktop drives focus on 1TB models (shown in blue), but we’ve also included results for other capacities where we were able to test these, plus results from a typical USB 2 desktop drive for comparison.

Portable drives analysis

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The figures in the graph above show how each portable drive performed in our real-world file-copy tests. This month, we’ve found large-file performance to be effectively identical in both directions, so we’ve combined read and write speeds into a single figure.

For the small-file test, average speeds are given for both read and write performance (slower speeds represent write results). Our reviews of portable drives focus on 500GB models (shown in blue), but we’ve also included results for other capacities where we were able to test these, plus results from a typical USB 2 portable drive for comparison.

USB 3.0 external HDD cost per gigabyte (cents)

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Conclusion

This month, we’ve focused on external drives in popular capacities: 500GB for portable drives and 1TB for desktop models. As our above graphs show, drives of the same capacity can perform quite differently – and the difference isn’t only between portable and desktop drives. In the portable pack, Iomega’s eGo is 30% faster than the Western Digital My Passport Essential, and LaCie’s premium Rugged drive is 10% faster again. (We give one figure for read/write performance as transfer speeds were identical in both directions.)

Fast sequential performance, however, doesn’t mean a drive will be speedy in all tasks. Our small-file tests stretch each drive’s controller and cache, and some models simply collapse. Among the portable drives, Seagate and Buffalo lagged some way behind the rest: in the desktop category it was Verbatim and Freecom that trailed, despite respectable performance in the large-file tests.

The performance scores we award to each drive weigh large- and small-file performance equally, but priorities may differ. If you want to archive video files, sequential performance is more important than random access; if you want an external drive for everyday use, or as a shared resource that might be accessed by several programs or PCs at once, small-file performance is arguably more important.

In our performance graphs we’ve also included scores from a few higher-capacity drives for comparison, as well as scores from a typical USB 2 model. It’s clear that even the slowest USB 3 drive will race ahead of a USB 2 model. We can also see that, for desktop drives, higher capacities tend to yield better performance – which is what we’d expect, as their greater data density means more data passes the internal read and write heads in a given period. This isn’t always the case for portable drives, however: we surmise that squeezing such high capacities into this small form factor involves performance compromises.

Finally, our table showing cost per gigabyte across the various drives and capacities (see below) indicates that larger drives are typically much better value than smaller ones – but with some caveats. In the portable market, 750GB drives are curiously expensive, and you can usually step up to a full terabyte model for only a few pounds more. In the case of the Seagate, you’ll actually pay less for the larger drive.

There’s also always a premium to pay for the highest capacities available. The 1.5TB portable drives offered by Seagate and Iomega are much more expensive, on a per-gigabyte basis, than 1TB models. In the desktop market, too, 3TB drives are less cost-effective than 2TB models, although here the gap isn’t so huge, and Buffalo’s 3TB DriveStation actually works out to be better value than the 1TB model.

View from the labs

The USB hard disk has been with us for more than a decade, and it’s easy to see why. It’s the easiest way to add storage to a computer, and it lets you carry around hundreds of gigabytes of data in your pocket. Now, with USB 3, there isn’t even a need to sacrifice speed for convenience.

But is USB 3 too late? USB hard disks rose to popularity in an era when a typical PC came with an 80GB hard disk. Today, 500GB or even a terabyte is par for the course – enough to accommodate extensive libraries of music, photos and videos. So fewer of us are reliant on external drives for everyday storage.

USB drives also pre-date widespread home broadband and mobile internet access. Today, we can keep our data in the cloud and access it from anywhere. We no longer need to carry bits of hardware around to get at our files: hence innovations such as the Google Chromebook.

Yet as anyone who’s waited for an HD movie to download will attest, the internet isn’t yet ready to replace high-capacity local storage. Nor does it offer the peace of mind that comes from having your files in your physical possession, stored safely on a secondary volume. That’s particularly germane when it comes to backups: in an emergency, an external drive is likely to be your fastest and most reliable recourse.

So external drives still offer advantages over internal and cloud storage – and some of them make pretty desk ornaments, too. The day will come when writing files to a USB hard disk seems as quaint as recording them onto a tape cassette, but for now there’s no need to feel guilty about investing in a fast, attractive, affordable USB 3 drive.