When buying a laptop or desktop, it's easy to get sucked into processor and RAM upgrades. However, no slight CPU boost improves day-to-day performance as much as switching from a slow hard drive to a fast SSD.

Unless you spend an awful lot of money, though, an SSD will not leave you with much spare space. A 1TB hard drive can costs a little as £40, a 1TB SSD around £240.

An external hard drive is, for many, the best solution. You can offload your data from your MacBook's SSD or your iMac's Fusion drive when it fills up, or keep one plugged in 24/7 as a store for any non-performance-critical data. A hard drive is perfect for music, video files and photos.

To find the best hard drive for your needs, you need to answer a few questions.

How much storage do I need?

Hard drive storage is relatively cheap. Unless you are really out to save your pennies, the smallest size of hard drive we'd recommend is 1TB.

Upgrades to 2TB, 3TB and even 4TB are also cost-effective, often making the bump up to the next model a good idea. Each terabyte can store around 11,000 music albums at 192kbps quality, but such storage doesn't seem so grand when you start archiving 4K video.

1GB of data will store as little as three minutes of 4K video shot with an iPhone 8.

Unless you're happy to have a digital bonfire every year, you also need to consider your future use. We'll use more data in the coming years, not less.

Portable or desktop?

If you think you'll be happy with a 1-4TB hard drive, you can buy a portable drive. These use small 2.5in disks, and as such they fit happily into a coat pocket.

They are usually bus-powered too. This means you just need to plug them into your desktop or laptop, no separate power supply required. There's just one cable, and the drive will barely take up any space.

If only an ultra-high capacity hard drive will do, consider a desktop unit. These use larger 3.5in drives, and tend to cover capacities from 4TB to 12TB.

They'll need to be plugged in for power. That's fine if they'll stay at home 95 per cent of the time, but they are not portable.

Ruggedisation

The choice is clear for those after a drive that can be connected anywhere. You need a 2.5in portable model.

Some of these also offer ruggedisation. Shock protection is the most important kind for a hard drive, as unlike an SSD they have moving parts that can be permanently damaged following a drop.

Rugged drives usually have some form of rubber coating that soaks up impact force, and a toughened enclosure that won't dent, crack or collapse under any normal amount of pressure.

A few also have water resistance. While few are rated IP67 like an iPhone X, meaning they can be submerged in water without damage, several can handle rain or water jets/splashes.

What extra features do you need?

Buy a larger drive, though, and you're more likely to get other features. Desktop units may have a built-in "hub", letting you plug in memory cards or peripherals using USB ports.

These are particularly useful if your current setup has limited connectivity, or the USBs you do have just aren't that handy.

Matching the hard drive's connector to those of your laptop is desktop is also essential. You'll get a cable in the box, but it will either terminate with a USB or USB-C shaped plug.

If you have an older MacBook, you'll want the older USB type. A USB-C connector is essential if you own a recent MacBook.

Not all USB-Cs are the same, though. MacBooks support Thunderbolt 3, which has eight times the bandwidth of USB 3.0.

However, in most cases you don't need to worry too much whether a hard drive uses USB 3.0 or Thunderbolt. The disks themselves just aren't quick enough to break through the data speed limits of normal USB 3.0.

Wireless and NAS

Aside from one special wireless hard drive from Western Digital, below you'll find predominantly "normal" external hard drives. There's another category you may want to consider too: a NAS.

These network-attached storage drives connect to your home Wi-Fi to share their data with other devices in your home. That might be a smart TV, Apple TV, a tablet or laptop.

A NAS is particularly useful if you want to set up a media server at home. This is like a wireless jukebox you can fill with videos, photos and music. Read our best NAS drives feature for more.

1. Seagate Backup Plus Hub: Best for high-capacity home storage

Seagate Backup Plus Hub

This one is the best for high-capacity home storage (and also the best overall).

Desktop-style hard drives may not seem that appealing when relatively high-capacity ones that fit in a pocket are affordable. However, there's still a real appeal to them particularly if they are never, or rarely, going to leave the office.

The Seagate Backup Plus Hub is a classic 3.5in desktop drive. It is available in sizes up to 10TB, and we're using this ultra-high capacity version. There's no difference in physical size between these variants, though.

It's 198mm deep, 118mm tall and 41mm deep, so not much larger than the 3.5in drive inside. The Seagate Backup Plus Hub does not have remotely Mac-like styling (although that is less true of the white, specifically Mac-focused model we will discuss in a moment) but there are some touches worth noticing. The sides are glossy black, the top, bottom and back a heat-dispersing honeycomb that looks fairly good.

A sloped front also stops it from looking like a plain plastic brick.

There are a few practical unique selling points too. The Seagate Backup Plus Hub has two powered USB 3.0 ports on its front. Place the drive intelligently in your setup and these could become the most convenient ports in your office.

You could use them to charge your phone or tablet.

The Seagate Backup Plus Hub is also designed to be used with both Windows and Mac OS computers. It is formatted using the NTFS file system, the standard for higher-capacity Windows drives. Just run the Mac user file pre-loaded on the drive and it'll install a driver that lets you write to the drive using OS X.

You can read a Windows-formatted drive with a Mac, but not normally write files to it. If you don't have both systems, though, you might as well reformat the Seagate Backup Hub Pro using OS X's Disk Utility app. It only takes a minute.

(The Mac version of the hard drive is formatted for Mac by default but you can download a Windows driver.)

This is a relatively long-standing model in the Seagate line-up, so it doesn't have a connection designed for Thunderbolt or USB-C 3.1 ports. A microUSB 3.0 socket sits on the back, which looks like a normal microUSB with a little sibling attached. The 1.2m cable ends in a normal USB port, perfect for older Macs.

You might expect lesser performance from a non-Thunderbolt drive, but the Seagate Backup Hub Pro 10TB's speed is excellent. There's a Seagate Barracuda Pro drive inside, which costs more than this drive when bought alone. Makes no sense, right?

It writes at up to 197MB/s and reads at an excellent 264MB/s. This is far better than the speed of a rival 2.5in HDD.

However, it also likely explains why the 10TB Seagate Backup Hub Pro is significantly more expensive than the 8TB version.

2. LaCie Mobile Drive: Best for travellers

LaCie Mobile Drive

This one is the best for travellers.

The LaCie Rugged Secure that we reviewed from LaCie last year is still on sale, and is a good option if you need a really tough portable drive that can take plenty of punishment when you're travelling or working on location. However, there's now only one version left - with 2TB storage - and LaCie introduced a newer range of Mobile Drives at CES earlier this year that provides a much wider range of options and also introduces a new 'diamond cut' design.

Rather than the neon-orange rubber bumper of the Rugged drives, the new Mobile Drives are wrapped in smart aluminium. They're available in two colours: 'moon silver' and, of course, 'space grey' that is intended to match the latest Mac models (and is only sold through the online Apple Store). The 'diamond cut' design simply refers to the exaggerated angular edges and corners of the drive, which look a bit like the facets of a carved diamond. Looks aside, the aluminium casing feels really sturdy - in fact, the 5TB model that we tested weighs in at 400g, and could give someone a serious concussion if you whacked them over the head with it.

There are smaller and lighter alternatives, though, depending on how much storage you need. Prices start at £70/$75 for a Mobile Drive with 1TB storage, while the 2TB model costs £95/$100. Those two drives measure just 10mm thick, 88mm wide and 122mm long, and weigh a more modest 200g.

The 5TB model is twice as heavy and twice as thick (20mm), and costs £160/$170. There's also a 4TB model, which is the same size and weight, but slightly less expensive at £140/$150.

The Mobile Drive has a single USB-C port on the back, but LaCie includes cables for both USB-C and the older USB 3.0, so you can use the drive with any Mac or PC.

The drives can be used with Time Machine for Mac backups, but LaCie's ToolKit app also allows you to 'mirror' individual folders. This is a good option if you use your Mac at work, and have individual projects organised in their own folders. Any folder that is 'mirrored' is automatically backed up and updated as soon as you make any changes to any file within that folder. This ensures that your backups are always up to date with the most recent versions of your files (whereas Time Machine still leaves a one-hour gap between backups).

Our only complaint here is that LaCie's skimpy manual doesn't provide much information about the ToolKit app, or the various formatting options for the drive, simply leaving you to wade through a bunch of FAQ files on its website.

That's our only complaint, though, and the Mobile Drive provides good performance, with write and read speeds both averaging out at 132MB/s in our tests - almost identical to the Rugged Secure drives - while backing up a 5GB batch of iTunes songs took exactly one minute.

3. Buffalo MiniStation Extreme: Best for extreme ruggedness

Buffalo MiniStation Extreme

Buffalo's MiniStation Extreme is slightly more expensive than some of its portable rivals, but it's a seriously tough and rugged little drive that will be a great option for people who work outdoors or who enjoy trekking across the Pennines for their holidays.

It does stick with a standard USB 3.0 interface, though, rather than the newer USB-C that is used on the latest MacBooks and Windows laptops. However, there are still millions of people who have USB 3 laptops, so there's certainly an audience for a rugged portable drive such as this.

The MiniStation Extreme is available with either 500GB, 1TB or 2TB storage, with prices around £64, £75 and £105 respectively (and the 1TB model is available in black, red or silver, while the other models stick with plain black). US readers can get the 1TB model for around $135 from HP.

It's not the smallest or lightest portable drive we've ever seen, measuring a rather chunky 21mm thick, 90mm wide and 141mm deep, and weighing in at 277g. You can't just slip it into your pocket when you're on the move, as you can do with some of the portable drives that we review here, but it won't be any trouble to carry it in a case along with your laptop when you're travelling.

And the size of the drive reflects its sturdy design, as the internal drive is wrapped up in a rubber-padded and shock-resistant casing that meets US military standards and is capable of resisting falls from a height of 1.2m. The case is also rated IP53, which means that it's both water- and dust-resistant, so it'll be ideal for use on building sites or in muddy fields at music festivals.

For extra convenience, the drive has an integrated USB cable that is permanently attached, and wrapped in a thick layer or rubber to help keep it safe. The cable is only about six inches long, but we were pleased to see that Buffalo also includes a USB extension cable in case the fixed cable isn't long enough.

Performance is fairly average, hitting a consistent 110MB/s for both read and write speeds, and the MiniStation Extreme took an acceptable 75 seconds to back up our 5GB batch of iTunes music files. That's perfectly adequate for routine backups when you're out and about, and the drive worked fine with Time Machine on my trusty old MacBook Air as well.

Our only minor complaint is that - once again - Buffalo seems a little uncertain about the Mac side of things.

The MiniStation Extreme arrived pre-formatted for a Windows PC, and the QuickStart guide told us to download a piece of software called Mode Changer in order to reformat the drive for use with a Mac. However, we had trouble locating the software on Buffalo's website - and the site also seemed to indicate that it wouldn't work with the current Mojave version of the macOS (although it did run perfectly well on Mojave once we'd managed to download it). The rather confusing hotch-potch of PDF help files was a little irritating as well.

Fortunately, you can use Apple's own Disk Utility to reformat the drive, so you don't need to spend too much time wading through Buffalo's website, and the ultra-rugged design of the MiniStation Extreme will ensure that it earns its keep when you're out in the soggy British summer, or working in harsh environments.

4. Seagate Backup Plus Ultra Touch: Best for MacBook owners

Seagate Backup Plus Ultra Touch

This one is the best for MacBook owners.

The Seagate Backup Plus Hub that we reviewed last year is still on sale online, and is an excellent option for desktop storage at home or in an office (and we've got one in our office, proving really useful with its extra USB ports). However, the company recently overhauled the Backup Plus range, putting more emphasis on portable drives for laptop users.

The new models are all compact, portable drives, although they offer a number of different designs and features. If you just want lots of extra storage at a competitive price then the Backup Plus Portable Drive offers either 4TB or 5TB for £125/$130 or £135/$160 respectively. Those large drives are a bit on the chunky side - 21mm thick - so Seagate also offers the Backup Plus Slim with either 1TB or 2TB storage instead. The Slim drives measure just 12mm thick, and cost £60/$80 with 1TB storage or £80/$100 with 2TB.

However, the top-of-the-range model is the new Backup Plus Ultra Touch. Like the Slim drives, the Ultra Touch is available with either 1TB or 2TB storage. It's slightly more expensive, costing £65/$90 and £85/$110 respectively, but has a stylish design that makes it a good companion for your MacBook, and also offers encryption to provide extra security for your important files and data.

The Ultra Touch measures just 12mm thick, 78mm wide and 115mm long, and weighs 151g, so you can easily slip it into a jacket pocket or a bag when you're travelling with your laptop. It's available in either black or white, and finished off with a smart woven fabric that makes a nice change from the dull monochrome colours of most hard drives. There's a standard USB 3.0 port on the back of the drive, and a USB 3.0 cable that will work with any Mac or PC, but Seagate also includes a USB-C adapter so that you can use it with new computers that have USB-C as well.

The Ultra Touch includes the same ToolKit app that is used with the LaCie Mobile Drive that we also review in this group test. The drive can be used for automatic Time Machine backups on your Mac, but you can also use the 'mirror' option in the ToolKit app to automatically back up individual folders so that they're always right up-to-date (and don't have to wait for Time Machine's hourly backups).

The ToolKit app also handles the encryption process for the Ultra Touch, although we found Seagate's manual - or lack thereof - to be rather unhelpful, leaving us to look around for FAQs and information about this encryption and other features on the company's website.

Performance is respectable enough, although the Ultra Plus won't win any awards for high-speed backups. It recorded write and read speeds of 125MB/s and 130MB/s in our tests, and took 110 seconds to back up a 5GB batch of iTunes music files. Even so, that performance will be fine for routine backups when you're travelling, and the encryption option will be really useful if you want to make sure that your private data stays private even if the drive is lost or stolen.

5. WD My Passport Wireless Pro: Best for home entertainment & photographers

WD My Passport Wireless Pro

This is the best for home entertainment & photographers.

It's also perhaps the most interesting drive on test here. You can use the WD My Passport Wireless Pro like a standard wired hard drive, but it also has integrated Wi-Fi and a 10-hour battery.

A thoroughly modern drive, it's setup using a mobile app (for iOS and Android) rather than a laptop. This teaches the WD Wireless Pro your home Wi-Fi network's login so it can become part of your home network.

Within a few minutes it'll appear as a shared network drive, accessible from your MacBook and other connected devices, such as smart TVs. You can view stored videos and photos directly from your phone, again using the app to access them.

Like other smart devices of this ilk, the app is both a strength and a weakness. It allows actions not possible with the average portable hard drive but does crash on occasion.

We like it most as a drive attached to a main laptop or desktop that can be accessed throughout the house without any extra setup involved. It can also be used to backup data wirelessly while out and about, connecting directly to the Wi-Fi networks the WD Wireless Pro transmits. It creates both 2.4GHz and 5GHz (ac) hotspots.

The WD Wireless Pro is great for versatility and convenience, but performance is not best-in-class. When connected with the cable it both reads and writes at up to 110MB/s, around 20MB/s less than the best-performing affordable 2.5in drives.

Also, transfer rates are naturally much slower when backing-up wirelessly. Using the drive's 5GHz band you can expect rates of around 20MB/s. It's a perfectly sound speed if you need to ferry over a few hundred megabytes of data. But if you want to transfer a fistful of gigabytes, plugging the drive in is a better idea.

It has a few extra features, though. The WD Wireless Pro has an SD card slot one side. It's a great way for photographers to back up files quickly out in the field.

There's a multi-purpose 4-LED array on the top too. This shows how much battery left, or how close a file transfer is to being complete.

To recharge the battery you plug the WD Wireless Pro in using the full-size USB port on the back. A smartphone-style power brick is included in the box.

The drive is, predictably, a lot larger than a standard portable hard drive because of all the extra tech required. Its footprint covers about twice the area of an ultra-portable alternative, and it's roughly 20 per cent thicker than a 3TB portable drive.

However, the WD Wireless Pro is still much smaller than a 3.5in external drive and it will fit into a small bag of rucksack with ease. Don't treat it too poorly, though, as it's an all-plastic enclosure with no official ruggedisation.

Remember to switch it off when you're done too as it will otherwise stay active until the battery runs dry. After a few hours' use the WD Wireless Pro's underside feels a little warm, which is no surprise when there is no fan inside.

6. LaCie 2big Dock Thunderbolt 3: Best for professionals and video editors

LaCie 2big Dock Thunderbolt 3

This is the best for professionals and video editors.

The LaCie 2big Dock Thunderbolt 3 is much more than just a hard drive. To start, it contains two drives, not just one. We are using the top-end config, which has two 10TB IronWolf Pro disks, designed to handle 300TB a year workloads.

They are enterprise class drives a cut above those you'd buy in a high street electronics shop. It instantly earns extra points for reliability.

Using such high-quality drives in a smart enclosure also lets the LaCie 2big Dock Thunderbolt 3 reach SSD-like speeds when reading and writing large files. We've recorded read speeds of 495MB/s and write speeds of 487MB/s, four times the speed of a standard external drive.

While that still looks slow next to the fastest M.2 SSDs, which can read at around 3500MB/s and write at 2100MB/s, it really isn't that much slower than the ~500MB/s SSDs used in most external drives. And 20TB's worth of SSD storage will currently cost you at least £4000.

Suddenly the LaCie 2big Dock Thunderbolt 3 20TB's £900-1000 price doesn't look so steep.

This isn't a NAS drive or a miniature server box, but it does have several important additional features. A simple LaCie application lets you switch to a RAID 1 setup, where the same data is written to the two drives simultaneously to protect against data loss. This also roughly halves the write speed, though.

You have to choose between great performance and good reliability, or great backup reliability and speed that is simply very good for an HDD.

Either way, the LaCie 2big Dock Thunderbolt 3 looks great next to an iMac. It has an all-aluminium enclosure and a light-up eyeball on the front that glows blue, or red when something has gone terribly wrong.

You're unlikely to encounter too many issues, though, because while this is a high-end unit it still has the simplicity of a consumer product. For example, you can just pull at the aluminium blocks at the front to open-up the drive bays, no cables involved.

The LaCie 2big Dock Thunderbolt 3's connectivity is comprehensive too. There's a 5Gbps USB-C port on the back, and two Thunderbolt 3s. This lets you daisy chain multiple drives.

There's even a full-size DisplayPort, which can pass through the video feed from a connected MacBook to a monitor. This introduces the other side of the 2big's personality, that of a dock.

USB 3.0, SD and CompactFlash connectors sit on the front, particularly useful for photographers.

Any complaints? As the IronWolf Pro drives inside run much hotter than most, the LaCie 2big Dock Thunderbolt 3 uses a fan that sits at the back. This is not a silent box, but the high-quality, low-noise Noctua fan is actually the least noticeable part. The operational noise of the drives themselves is more evident than that of a lower-performance 2.5in drive.

We don't think this is a big issue, but is something to bear in mind if you're looking to plug into an often virtually silent MacBook.

7. Toshiba Canvio Advance 2TB: Best for classy design at a lower price

Toshiba Canvio Advance 2TB

This one is best for classy design at a lower price.

When buying a hard drive for your Mac, you don't necessarily have to opt for one that is plug-and-play ready. The Toshiba Canvio Advance 2TB is very similar to the firm's "Premium for Mac" hard drives. It just comes formatted for Windows and doesn't have a MacBook-matching design.

So how do you get it ready for macOS? Run DiskUtility and you can reformat the drive in about a minute. That's it: you're ready. And you save up to around £15/$20 compared with the Mac-specific version. Reformatting also offers the option to use the drive for MacOS's Time Machine backup feature.

The main difference, other than formatting, is the construction. Toshiba's Canvio Advance 2TB has a semi-gloss plastic shell, instead of an aluminium one. Its white version is a great stylistic fit for Macs and MacBooks.

This isn't just down to the colour. At 14mm thick, the 2TB model is not much taller than the keyboards of older-generation MacBooks. There are black, red and blue finishes too, if you want to mix up the look a little.

It's a better option for older hardware in general too, as the Toshiba Canvio Advance 2TB comes with a full-size USB cable rather than a Thunderbolt-style USB-C. The connector on the actual drive is a micro USB 3.0, which looks like a microUSB with another half-a-USB tacked on.

If you've got a brand-new MacBook, you may want your hard drive to match its ports. However, as this is a hard drive, not an ultra-fast SSD, there's actually no real performance sacrifice.

The Toshiba Canvio Advance 2TB reads at an average 140.2MB/s when transferring 5GB of files. And it writes the same 5GB at 120.3MB. It's very similar to the results of the "Premium for Mac" version we tested, and you'll see slight variance in the speeds between different capacities anyway.

The LED is the one other little Toshiba extra. When attached to a USB 2.0 port it glows white, turning blue when it's hooked up over USB 3.0. It's a good way to tell if you're getting the best from the drive. If it's white, switch that port.

There's one little part you miss out on when using the Toshiba Canvio Advance 2TB with a Mac. It comes with an encryption tool that lets you password-protect the entire drive. This is lost when you reformat it. However, you'll only want to use this if you really need extra security for your files. Forget the password and you can't access your data either: a nightmare scenario.

The Toshiba Canvio Advance is a good, pocket-size hard drive that's a great fit for slightly older MacBooks in particular. We tested (and recommend) the 2TB model, but it's also available in 1TB and 3TB flavours.