Choosing the best hard disk drives, external drives and storage: Buyer’s Guide review

hard drives and external drives
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One of the most common types of PC component to be upgraded is its storage. Whether it’s adding more space for you films, music, and photos, or simply a way of boosting the overall performance of a seemingly sluggish system, there are a few key things you should know before you get out your credit card, starting with exactly what sort of a drive you’re going to need to buy. IT Reviews survey the options.

This guide deals with hard disk and solid-state storage. If you’re looking to replace an optical (CD or DVD) drive, consult our specific guide to replacing CD, DVD and Blu-ray drives. Everyone else… read on.

Types of connection
How you go about upgrading your storage depends on the type of PC you have – desktop or notebook. While the hard disk in a laptop can be replaced with relative ease, many users prefer not to tinker about inside their machine. For these users, and external drive makes the most sense. We’ll deal with the on the next page.

If you’re upgrading a desktop PC, on the other hand, one of the first things you’ll need to find out before you can add to your machine’s internal storage is the type of connection it uses. In all but a few very old systems, this falls into two camps: IDE or SATA.

If your computer is getting a bit long in tooth, the chances are that it uses an IDE connector for both its hard drive and its optical drive(s). A previous-generation technology, IDE – also known as EIDE or Parallel ATA – uses a wide, 40-pin connector which offers a limited maximum performance compared to modern SATA drives.

IDE doesn’t prove as much of a bottleneck for internal CD and DVD drives, which are typically limited more by the speed at which data can be written and read to the discs themselves, but if your system still uses IDE for its hard drive you may struggle to find a cheap drive as an upgrade. Many IDE drives on the market these days are specialist items designed as emergency replacements or for older servers, meaning you’ll be paying through the nose for outdated technology.

Thankfully, there’s a solution: it’s possible to buy an add-in card which connects to your computer’s motherboard using a PCI or PCI Express slot and adds in two or more SATA ports – the modern replacement for IDE. These cards, which typically start at just £10 or £15, will allow you to upgrade to a much faster drive for a significant saving over an IDE equivalent.

The modern replacement for IDE, SATA – short for Serial ATA – allows for several times the overall bandwidth down a narrow cable that takes up less room in a system than an IDE ribbon cable. Better yet, the SATA standard connector is shared between both desktop hard drives, which are 3.5in wide, and laptop hard drives, which measure 2.5in – making it easy to use either size of drive in your system, using special mounting brackets to physically fit the smaller type of drive.

Hitachi GST - Deskstar 7K3000 3TB (HDS723030ALA640)

Modern SATA internal hard disks are currently available with capacities up to 3 terabytes (3TB), like the Hitachi Deskstar 7K3000, shown in exploded view above.

The SATA standard is now ubiquitous for both hard drives and optical drives. Devices based on the last generation standard – SATA 3.0Gbit/s – are cheap, and although the latest SATA 6.0Gbit/s devices remain relatively expensive at the moment the cost will come down in time. All SATA devices are backwards-compatible. If you have a SATA 6.0Gbit/s port on your system, it will accept SATA 3.0Gbit/s and SATA 1.5Gbit/s drives – but only at the speed of the older connection, so expect to take a performance penalty compared to the manufacturers’ stated specs.

IDE and SATA optical drive connections

The picture above shows IDE (top) and SATA connectors, and their corresponding ports at the rear of drives. The drives shown in the image are DVD writers, but similar connections are found at the rear of hard disks.

Compatibility and features
When you’re upgrading an internal hard drive, there are several aspects to consider.

Spin speed
The speed of the drive is one of them: measured in revolutions per minute, or RPM, it can make a real difference to the performance of the drive. For a standard desktop system, try to aim for a 7,200RPM drive. Although faster drives are available – including 10,000RPM and 15,000RPM models – they’re usually aimed at high-performance servers and come with a major price tag for a minor performance gain.

If you’re more worried about the heat or noise generated by a fast-spinning drive, such as if you’re buying a drive for a home theatre system or to fit into a compact case, look towards the 5,400RPM end of the market. You’ll take a small performance hit, but these drives draw less power and put out less heat than their larger counterparts. For laptops, this can spell an improvement in battery life.

The next thing to look at is cache size. Cache is a very expensive form of memory which performs extremely quickly, and is used to store recently accessed data from the drive. The larger the cache that comes with the drive, the better it will perform. It’s uneconomical to consider less than 16MB cache in a modern drive – the cost savings aren’t worth the performance hit – and 32MB is pretty commonplace.

Strange as it may sound, the last thing you should look at is the capacity. No matter how big a drive you buy now, you will find a way to fill it. As people start recording high-definition video at home, downloading vast quantities of music, and installing the latest games, it’s becoming increasingly easy to fill drives – so always buy the biggest drive you can afford at the time.

If you’re buying for a laptop, you’ll need a 2.5in drive – and there’s an extra point to consider: thickness. Whereas most desktop drives are a standard thickness, laptop drives differ – and while the difference is only a few millimetres, it can mean that certain drives won’t fit. Check with your manufacturer to find out the maximum drive size that your laptop will take – or, alternatively, find out what thickness the current drive is and try to find one to match.

While laptop-sized 2.5in drives can be mounted in the 3.5in bays of a desktop computer, there’s little reason to do so: laptop drives are typically slower than their larger equivalents, and come at a higher cost for a lower capacity. The only exception to this rule is when it comes to SSDs, which we’ll deal with next.

Solid-State Disk (SSD) drives
If you’re looking for a boost in performance, rather than capacity, solid-state storage is definitely worth looking in to. SSDs replace the spinning magnetic platters of a traditional hard drive with chips of flash memory – meaning they run silently, draw very little power, and are typically extremely fast. They are also more robust than a mechanical hard drive, with no moving parts to be shocked if you should drop your laptop while it’s running.

The majority of SSDs on the market today are 2.5in models, the same size as a laptop hard drive – but they’re used in both laptops and desktops to provide a serious speed boost. In terms of the time it takes to load data – such as opening a program, booting the system from cold, or loading levels in a game – upgrading to an SSD can offer the greatest overall improvement in performance to a system.

Because there are no spinning platters to contend with, SSDs can offer read and write speeds of 300MB/s and beyond – a major improvement over mechanical drives, which are typically closer to 80MB/s at the consumer level. The lack of moving parts also mean they’re robust, shockproof, and draw less power – all good news for laptop users, who can expect a boost in battery life as a result.

OCZ Technology Vertex 3
OCZ Technology’s Vertex 3 120GB model is the fastest SSD we’ve so far seen.

SSDs aren’t without their drawbacks, however. Current models are significantly more expensive per gigabyte than a mechanical drive – you can expect to pay more for a 64GB SSD than a 2TB hard drive. There are also questions about their long term reliability – as an SSD is written to, it ‘wears,’ and while technologies have been introduced to minimise the impact this causes, they’re still not suitable for users who frequently write vast quantities of data to their drives.

For those looking for a half-and-half solution, some companies – including Seagate – offer ‘hybrid drives,’ which combine a small SSD with a traditional mechanical drive. Although they don’t offer all the advantages of a true SSD, they can offer a moderate speed boost for a much cheaper outlay than going pure-SSD.

Continue to the next page for our guide to choosing an external storage drive.

If you’re not quite confident enough to start fiddling around inside your PC, or if you’re looking for a portable solution to your storage needs that you can swap between different machines, think about an external hard drive. While you’ll pay a premium over the cost of an internal drive of the same capacity, the cost isn’t usually that much higher. Sadly, it will come at a cost of performance: with certain exceptions, external drives just don’t work as quickly as an internal equivalent of the same specification.

Most external hard drives use USB 2.0, the second-generation version of the Universal Serial Bus standard. This allows for reasonably fast read speeds, and carries enough power – if you use the supplied double-ended cable – to run a smaller 2.5in drive without the need to plug it into the mains. While that’s not a requirement for desktop users, it’s a handy thing to have for a drive you’ll use with a laptop – and certainly worth paying the few pounds extra it costs to get one that is ‘bus-powered,’ as the technology is known.

Iomega - eGo Portable 500GB
Some portable disk drives such as Iomega’s eGo are designed with rugged shock protection.

Some newer drives use the USB 3.0 standard, which is even faster and approaches the speed of modern internal connectivity such as SATA. These are still relatively rare, but if you’re looking to splash out it’s a good option, as it’s backwards-compatible with USB 2.0. A USB 3.0 hard drive will work (albeit at a reduced speed) on almost any system using USB 2.0, and will reveal its hidden potential as and when you upgrade.

FireWire (IEEE 1394)
Those looking to add external storage to an older Apple Mac might want to look into FireWire, technically known as IEEE 1394. Although not as popular as USB, FireWire offers impressive transfer speeds, and drives equipped with the right port can be had fairly cheaply.

If you’re looking for a device you can use on multiple systems, however, FireWire isn’t the best choice: PCs rarely include FireWire ports, and Apple has recently dropped them in favour of the new Thunderbolt port on its latest models.

Thunderbolt, if your system has it, is a great choice: offering up to 10Gbit/s of aggregate performance, a Thunderbolt port even eclipses the speed of SATA for data transfer. Sadly, unless you’ve got one of the very latest Apple Macs, it’s not an option – and even if you’re lukcy enough to have one of these new machines, Thunderbolt drives are still thin on the ground. ESATA – for External SATA – is another choice if you absolutely need the fastest speeds, but check their power requirements: most ESATA drives need to be connected to the mains, making them less portable than a USB equivalent.

USB flash memory drives
For smaller files, ultr-compact and pocketable USB memory drives – often ‘thumb drives’ because of their diminutive size – are the best option. These come with a USB plug built in, and generally transfer files by USB 2.0. Although an increasing number now take advantage of the theoretically faster speeds made possible by USB 3.0, in practice these lightning-fast file transfers are hampered by the drive’s internal electronics, meaning that in real-world testing we haven’t seen vast improvement.