Buyer's Guide: The Best External Hard Drives

If you want to keep a reliable backup of your data without piling up the CDs and DVDs, or if you've just run out of space elsewhere--you've got two options:

• the DIY approach: you can get a screwdriver out and either add a new hard drive inside your computer or install a hard drive in an enclosure; or
• the easy way out: choose an external hard drive like the ones in these tests.

Prices haven't really fallen that much in the past year, so you should expect to pay around £100 for one of the larger external hard drives on the market.  What has changed, though, is the amount of storage you get for your money: the current generation of 500 GB drives are great for storing collections of thousands of photos and videos, for example.

Speeds: 30 MBps over USB, and up to 80 MBps over eSATA

Speeds have also been improving, mostly because of the growing popularity of two connections that used to be reserved for professionals: FireWire and eSATA.  Some of the disks we tested reached speeds of 80 MBps, meaning you'll only need a minute to copy the equivalent of an entire DVD: 4.5 GB.  That effectively makes DVD burners seem useless—and they're a lot more expensive, too.

Checking how fast a hard drive can copy data is one thing, but it's not the only important factor.  You should also consider how quiet the drive is, whether you like its design and how much power it consumes.  We therefore measure noise levels, both with and without 'silent' mode (AAM) activated, when it's available, as well as energy consumption.