Hard drive buying guide

We walk you through the process of buying a new hard drive, and explain all the jargon: from network-attached storage to solid-stated drives

Solid-state drives offer numerous benefits over traditional hard drives, including shorter seek and access times and greater durability due to the lack of moving parts. These drives are commonly found in a 2.5in form factor — the same size as most notebook hard drives — and are normally utilised in personal media players, netbooks and notebooks. However, SSDs are more expensive than conventional hard drives and have a higher cost per gigabyte. Solid-state drives also commonly have lower capacities than traditional hard drives, and so they won't as easily meet the needs of high-capacity workloads.

As the technology behind solid-state drives matures and prices drop, the drives will become more appealing options.


For many users, the most important feature of a hard disk is how much data it can store. The maximum capacity of hard drives is continually increasing due to advances in technology. These days most laptops are fitted with a 2.5in, 160GB hard drive, while mid-range PCs use a 3.5in, 200GB-500GB hard drive. The highest capacity hard drives designed for use by consumers offer 2TB of storage. Most people won't need this much space (unless they have a lot of music and videos). A hard drive with 250-500GB of storage should be more than enough for most people, but it's worth checking how much space your collection of video and audio files takes up. The cost per gigabyte of hard drives tends to be 15-20c, with premium and ultra-high-capacity models costing more.

How you will use a hard disk will determine how much space is required. In consumer PCs, much of the space on the hard drive will be consumed by media files. If you plan to store a lot of media — especially video, but also audio — you need a big hard disk (especially if you plan to leave the media on the hard disk permanently, rather than archive it to DVD). The following list should give you a rough estimate of the amount of space different types of file will occupy on a hard disk.

• The operating system: 7-8GB (though this can be up to 16GB in some cases).

• An office suite: 2-3GB.

• A fully installed computer game: 4-8GB or more.

• A CD directly copied to hard disk: 400-700MB.

• A single MP3 music file: 5-10MB (depending on quality).

• A full album of MP3 files: 60-120MB (depending on quality).

• A DVD directly copied to the hard disk: 4-8GB.

• A DVD movie compressed to DivX (such as a downloaded movie): 700MB - 1.4GB.

• A Blu-Ray movie compressed to DivX: 2.5-4GB.

• Compressed home video footage: 1GB-2.5GB per hour (depending on resolution and quality).

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