Keep your data safe External hard drives

External hard drives add storage space to a computer that’s groaning under the weight of large software and music files. Plus, they’re a great place to keep copies of all your important data should your hard drive break.

Desktop/standalone drives

Desktop drives sit next to your PC, connected most (if not all) of the time. They come with an external power supply (transformer) that needs its own mains plug. 

All the desktop drives we tested connect to your PC via USB, but some (such as the Western Digital My Book Home in our test) also connect via FireWire or eSata, too.

Choose a desktop drive if you want to add extra storage space to your PC (for carrying out backups) but don’t need to carry data from place to place.

Portable drives

Portable hard drives are now impressively tiny – about the size of a pack of playing cards. They don’t need a separate external power supply, but instead draw the power from the PC via the USB cable.

Usually they use a special double-ended cable, taking power from two of the PC’s USB ports. Although they tend to have less storage space than desktop drives, their small size and lack of external power supply means they’re ideal for people who need to carry their data with them.

Network drives

If you have a home network, you could consider a network hard disk, which you can connect to your network so everyone can save their files onto it. The speed of a drive on your network will be directly affected by the slowest part of the network – for example your Wi-Fi connection or your router. For this reason, the speed of these drives is less of an issue and ease of setup and use should be a more important consideration.


External hard drives are connected to your computer via a cable. The most common type is USB 2.0, which will be compatible with most modern computers.

However, you’ll also find drives with FireWire connections (found on Macs as well as many PCs these days), Ethernet connections (for use with networks) and eSata connections.

Drive formats

You may come across the terms FAT32 and NTFS when you’re choosing hard drives - they describe the way the data is stored inside the disk. The maximum single file size you can save to a drive with the FAT32 format is 4GB.

This should be more than adequate for most people, but if you want to store much bigger files, it’s worth either buying an NTFS drive or converting the drive from FAT32 to NTFS (see your drive’s manual for details).

Apple Macs can’t save to the NTFS format, so Mac users should use either FAT32 or an alternative format known as HFS (again, consult the drive’s manual for more on this format).