A few years ago, the idea of owning a 1TB+ external hard drive would have seemed excessive to most users. These days, it can fill up awfully fast.
Movie downloads, HD video editing and computer games all eat up handfuls of gigabytes at a time. A consequence is that it has become increasingly essential to top up your PC's storage capacity on a semi-regular basis - and that’s before you even think about making offline backups.
External HDDs come in a wide range of shapes, capacities and sizes.
Fortunately, HDD storage is now cheaper than ever, with 1TB models frequently selling for well under $100. The exception is external SSD storage, which remains prohibitively expensive. However, for most users a conventional hard disk will be more than adequate for everyday computing.
Need for Speed: 10 Solid-State Drives Reviewed
In the following article, we go through some of the HDD basics and highlight a few impressive deals that have caught out eye online.
How much storage space do I need?
Deciding what capacity hard drive to buy comes down to your personal computing habits. If you're a prolific downloader who likes to hold onto every TV show and movie, you can never have 'too much' storage. On the other hand, if your media library is limited to music, photos and the occasional video, you can probably get by with a 500GB model.
Typically, a 500GB hard drive will be able to store around 40 hours of video; although this varies considerably depending on format type and resolution. Most hard drives claim to be capable of storing hundreds of thousands of images, but again, this all depends on the resolution and file size of your photos.
The Hitachi 3TB XL packs three terabytes into a single enclosure.
Meanwhile, an average full-price computer game usually requires around 8GB of installation space. If you prefer to dip in and out of multiple games (as opposed to sticking to one or two titles), you're better off going for a bigger hard drive.
As a general rule, it's a good idea to get more storage than you think you need. If you're security-conscious, try to match your main PC's internal storage so you can make a complete backup.
Hard drive speeds: 5400rpm vs 7200rpm
Hard drive speeds are determined by the rotational speed of the platters. This is measured in revolutions per minute (usually shortened to 'RPM'). In other words, a 7200rpm hard drive will be able to access data faster than a 5400rpm hard drive. A faster hard drive will cut down on the time it takes to transfer files, which is handy for external hard drives where files are regularly moved from one drive to another.
As you'd expect, 7200rpm drives usually go for a higher premium, which is something budget shoppers will need to keep in mind. It's also worth noting that large capacity hard drives tend to have faster access times than their small capacity equivalents.
However, not all external hard drives are equal. Read/write speeds, which are measured in megabites per second (Mbps), can vary greatly between models, even if both hard drives have the same rotational speed. This information can usually be found on the back of the box, but you should always take it with a grain of salt.
Which form factor?
External hard drives come in two main form factors - 3.5in and 2.5in. Note that these sizes refer to the internal drives, and have no relation to the size of the external HDD enclosure. (Indeed, many external hard drives contain multiple HDD platters, which makes them considerably bulkier.)
Pictured 2.5in and 3.5in HDDs - you will find one or more of these inside your external hard drive.
3.5in external hard drives are generally designed for desktop use and may require an AC power adaptor (this will be supplied). They tend to be fairly bulky and are less suited for travel. On the plus side, they provide greater storage capacities, with some models offering up to 4TB of storage space.
2.5in external hard drives, meanwhile, are more lightweight and usually draw power from your PC/laptop's USB port. Some portable hard drives also come with extra layers of protection, such as added shock-resistance and water-proof casing. On the downside, they do not offer as much storage space as the biggest HDD desktop models on the market.
Bear in mind that these are not hard and fast rules - some desktop models contain 2.5in hard drives while some 3.5in hard drives are suitably portable.
OVER PAGE: USB 2.0 vs. USB 3.0, buying HDDs for tablets, bundled software...