Storage devices show quite how far miniaturisation has come over the years more than almost any other area of tech. We have memories from the 1990s of installing applications on fistfuls of 1.44MB floppy disks. Nowadays, a microSD fits 400GB into the size of your thumbnail.

However, portable SSDs (solid-state drives, or flash drives) offer the best combination of portability and performance if you want a drive to plug into your Mac. They are one of the most effective ways to upgrade and speed up a Mac.

SSDs are the key to truly fast day-to-day navigation of an operating system: the solid state drives in the latest MacBooks are up to 30 times faster than a hard drive. So in this article we round up the best SSDs for a Mac owner.

If you want to skip our general buying advice and see our SSD recommendations, you can click here to jump straight to the products. We focus primarily on the more popular external (portable) type of SSD, but the Samsung 860 EVO is a good budget choice if you want an internal SSD.

SSDs vs hard drives

Cost per gigabyte is the main stumbling block. You might pay £340 for a 1TB portable SSD, whereas a 1TB external hard drive costs around £50.

That's 34p per gigabyte in SSD land, or 5p with a hard drive.

This is because hard drives use relatively cheap spinning platters to store data. SSDs employ NAND memory chips. They are pricier, but also faster and allow for much smaller enclosures.

If you decide in favour of hard drives, see our roundup of the best Mac hard drives.

2.5in or ultra-portable?

SSD performance varies from around 300-500MB/s read speeds all the way up to 3000MB/s, but there are three basic physical forms of SSD. And two can be considered portable.

'Naked' SSD boards plug directly into PCIe or SATA interfaces. These are the kind you might use to replace the SSD in a laptop, or add to a desktop. They are not really portable.

2.5in SSDs offer a mix of portability and internal use, and are the cheapest way to get a portable drive. They have a plastic casing, avoiding damage to the components, but use SATA connectors rather than USB.

You can buy an enclosure to get more protection and that all-important USB or Thunderbolt interface, or even just use a SATA-to-USB cable. We use one of these cables in the office to ferry around test files on a 2.5in SSD.

For the ultimate portable experience you need a 'pocket' SSD, though, not one based on 2.5in drive dimensions. These are designed to be used with USB or Thunderbolt connectors, not those found inside a Mac or MacBook.

You'll mostly find this kind below. They are incredibly small and convenient. However, they are more expensive than 2.5in-style drives, so you may want to consider the larger type if lower spend is a top concern.

Shock-proof, and rugged?

SSDs are more durable than hard drives. They have no moving parts, and won't be damaged if they are moved or knocked while writing data. While modern hard drives have some level of shock protection, it's still a big issue.

You can treat an SSD pretty mean before it starts complaining.

Some portable SSDs even offer water resistance. You can also get ruggedisation in a specialised drive enclosure, if you choose to go down the 2.5in drive route.

This is a huge portability benefit. But if they are sat still all day, are SSDs more reliable than HDDs? Hard drives tend to fail mechanically. For example, the motor that spins the platters might burn out. SSDs' memory cells age, which can lead to failure. Both kinds require specialist recovery. As ever, back up important data.

However, for our purposes, as people who occasionally have to fling drives in rucksacks and plug them in while sat in an airplane seat, SSDs are the clear winner.

Matching SSD performance to your connectors

How fast can you expect SSD file transfers to be? The top external SSDs can read and write at up to around 550MB/s.

However, to get these speeds you need a port on your Mac or MacBook that can handle this bandwidth.

If you've got a recent model with a Thunderbolt 3 USB-C port, you're set. While external SSDs use USB 3.1 standards rather than Thunderbolt, the port also supports USB 3.1 Gen 1 and Gen 2, which is what we're after.

Have an older machine with USB 3.0 or USB 2.0 ports? You'll see some speed compromise.

USB 3.0 can hack most of an external SSD's speed, with theoretical max of 625MB/s, or a chunk lower in real-world use. Think twice if your computer is rather old, say a 2011 MacBook Pro, and only has USB 2.0 ports. These max out at 60MB/s, which just can't do justice to these ultra-fast SSDs. In that case, consider a hard drive instead.

How much storage do I need?

Recent external SSDs tend to come in three or four capacities: 250GB, 500GB, 1TB and in some cases 2TB.

You'll want to think carefully about the capacity you need, as the cost difference between 500GB and 1TB models is usually stark. There aren't the same relatively minor price leaps seen in 1-4TB hard drives.

We can't answer this one for you, but it's a good idea to do a quick mental calculation. For example, 4K footage from a Panasonic Lumix GH4 camera eats up 4GB every five minutes. Video editors who work in 4K need a lot of storage.

However, if you just need to back up or carry around some movies and photos, a smaller-capacity model may well do the trick. Check out your Mac's own storage capacity and use that as a guide.

Basics sorted, let's get on to the drives.

Best SSD for Mac

1. SanDisk Extreme SSD

SanDisk Extreme SSD

The SanDisk Extreme is the best combo of portability and rugged build of any of the SSDs we looked at. It's also our favourite portable SSD of the moment, with a few little design touches that make it the handiest model around for portable use.

First, it's tiny. The shape of a shrunken mobile phone, it fits easily into a pocket and is less wide than either the Seagate or Samsung alternatives.

A cut-out at one end also lets you attach it to a bag or belt using a carabiner. You could even add it to a keyring. But this little fellow deserves better than a life in a pocket, jangling around with loose change.

Its design also seems much less serious than most of the competition. Two-tone orange and blue, the look has more in common with a lifestyle Bluetooth speaker than a plain old computer component.

The SanDisk Extreme SSD's casing has rubbery edges, which won't get damaged as easily as metal if you drop the drive. Most portable SSDs are made to withstand drop impacts, but here even the finish is. Its front is plastic, though, with little shallow dot indents that, yet again, make it look less serious than some others.

It's shock-resistant to 1500G and has IP55 water and dust resistance. This means the SanDisk Extreme SSD can handle water jets in any direction without harm. In more practical terms, IP55 gadgets like this can't be submerged in water, but don't mind rain.

SanDisk has done its best to make sure you can use the SSD with any computer too. There's a single cable in the box, but a little adapter means you can switch the terminal between a Thunderbolt 3-style USB-C or a trusty old full-size USB.

It uses the exFAT file system, so is plug-and-play-ready for your Mac, and will play nice with Windows machines too. On the drive itself you'll find a link to download SanDisk's SecureAccess app.

This lets you password-protect selected files and folders. You can let the app give you a password 'hint' if you have a tendency to forget logins, but make sure it's a good one as the files are encrypted, and won't be recoverable without the password.

And performance? Used over a USB 3.1 Gen2 USB-C port we recorded read speeds of 535MB/s and writes of 476MB/s, very similar to the speeds of the Samsung and Seagate alternatives. You can transfer 5GB of files in as little as 10 seconds.

Is there anything we'd change? A little carry pouch would be a welcome extra, not to mention a smart way to avoid losing the USB adapter. We can already imagine losing it, and only finding it again when moving house several years into the future.

The price is also in line with Samsung's T5, and some of you may prefer that drive's 'executive chic' aluminium casing.

2. G-Technology G-Drive Mobile SSD

G-Technology G-Drive Mobile SSD

You may not have heard of G-Technology, but it makes one of the best portable SSDs around. Not only is this one of the most Mac-centric models you can buy, it's among the toughest, too.

The Mac angle is not obvious in the G-Drive Mobile SSD's design, though. A big silver G on the front and hints of bright blue under a faux grille make this drive look more like a movie prop than a natural fit for a minimalist MacBook home office.

At least it's not boring, though, right?

The G-Technology G-Drive Mobile's shape is similar to SanDisk's. This drive is taller than it is wide. It's pocketable, but chunkier than most drives on test at 1.45cm thick.

The slight extra bulk is more than justified. This is one of the toughest SSDs available, and there's no price jump over non-rugged alternatives. The G-Drive Mobile is certified to IP67, meaning it can be submerged in water at a depth of 1m with no ill effects.

It doesn't need a rubber bung over the USB-C port to achieve this, either. Like the charge sockets on some higher-end phones, it's water-resistant by design.

The G-Technology G-Drive Mobile's impact and tensile strength are better than the competition too. It's drop-tested to 3m, rather than the 2m seen elsewhere, and can take 1,000lb of pressure without breaking. None of this is obvious from the feel, as the outer is all plastic. That includes, sadly, the top cap, which looks like aluminium.

This drive is tougher than the SanDisk Extreme SSD, much as that drive's design seems better prepped for a life outdoors. SanDisk's finish will look better after a drop on gravel.

Short USB-C and USB-A (full-size USB) cables are included, letting you plug the G-Drive Mobile into any MacBook or iMac. Unusually, the drive also comes ready-formatted just for macOS, rather than using the cross-platform ExFat. This offers slightly better performance with certain kinds of file juggling, although you can reformat it using Disk Utility if you need it to bridge Mac and Windows systems.

The G-Drive Mobile SSD's performance is comparable with that of the Samsung T5: they are both USB-C Gen 2 devices and have similar SSD hardware inside. It reads at up to 530MB/s and writes at 479MB/s, a whopping 3MB/s more than we recorded with the Samsung.

G-Technology also makes a 'Pro' version of the G-Drive Mobile with speeds of up to 2800MB/s. This sort of speed demands a Thunderbolt 3 port, added to MacBook Pro models in 2016. However, the drive is also almost twice the size. And four times the price.

The standard G-Drive Mobile's price is entirely reasonable, but as there's no 250GB option those wanting to spend under £100/$100 need to look elsewhere. There are currently only 500GB, 1TB and 2TB models. This is the most rugged drive on test, although it's you'll see the effects of bumps and scrapes more than in the SanDisk Extreme SSD.

3. Samsung Portable SSD T5

Samsung Portable SSD T5

This SSD gets top marks for its small size and metal build.

Samsung makes many of the most popular SSDs. Its Samsung T5 is like a shrunk-down version of the 2.5in model you might put into a desktop.

This is a smart, no-nonsense portable SSD with great performance and tough build. Its frame is a 'unibody' piece of curved aluminium, with plates of soft touch plastic on each end.

Samsung says the T5 is drop-tested from 2m height, and the shell feels like it could take being trodden on. Even the idea of this makes us wince, though.

Like other aluminium finishes, knocks and scrapes will damage the paint job. The Samsung T5 can handle punishment, but it doesn't welcome it like SanDisk's SSD.

The colour also depends on the model you choose. Ours is a 1TB, which comes in black, like the 2TB version. Lower-capacity 250GB and 500GB versions use a bright blue shade.

With a footprint a little smaller than a business card and 10.5mm thickness, this feels like the perfect fit for a smart laptop bag. It's 74mm long and 57.3mm tall.

However, it's not water-resistant. This is a portable SSD for work commutes, not trekking across jungles.

In the box you get two 40cm-ish cables. One has a USB-C connector at the end, the other a traditional USB. You can file the one you don't need away in that box of assorted cables and adapters many of us have in a cupboard somewhere.

As it's exFat-formatted, the Samsung T5 works with Macs as soon as you plug it in. There's also software on the drive. This simply lets you password-protect the entire drive's contents, using 256-bit encryption. It's either on or off: you don't create a virtual protected 'vault' of encrypted files, so many of you won't want to use this feature.

The app only recognised the drive when we used Samsung's supplied cable, failing to do so when we tried a phone's charge cable. It was only the app that had the issue, though. The drive itself functioned perfectly fine with the 'intruder' wire.

There's even an app for phones too, with the same security measures. However, it's for Androids, not iPhones.

Used over a USB 3.1 Gen 2 compatible socket we recorded read speeds of 525MB/s and writes of 478MB/s. As such it's on par with the other top portable SSDs you can buy right now.

What else sets it apart? The Samsung T5 has a little blue LED by the connector that shines when the drive is connected. It sits under a layer of plastic, though, so is not at all distracting.

4. Seagate Fast SSD

Seagate Fast SSD

This SSD is our favourite in terms of MacBook-matching style.

The Seagate Fast SSD is perhaps the most sophisticated-looking drive around at present. It has a roughened dark grey plastic housing with a plate of anodised aluminium on top. It'll look great next to a MacBook.

However, this is also easily the largest of the USB-interface portables in this article. It's only 9mm thick, but is 79mm wide, almost twice the width of the SanDisk Extreme SSD. The Seagate won't disappear into a pocket quite as easily as the Samsung or SanDisk models.

But will it fit in a jeans pocket? Absolutely.

There's a bright white power and operation LED on one edge, and a USB-C connector on the drive itself. Cables with USB-C and USB-A (standard USB) terminals are included in the box. The Seagate Fast SSD is ready to play with old and new Macs alike.

It uses a USB 3.1 Gen 2 interface, and when plugged into a socket with that spec you'll see read speeds of 528MB/s and writes of 478MB/s. These are very similar results to what we saw from the Samsung T5 and SanDisk Extreme SSD.

You lose the water resistance of the SanDisk and while the drive is shock-proof, there are no claims about specific drop testing.

If the Seagate Fast SSD is only as fast as the competition but larger and less rugged, why does it earn a place here? First, there's the design.

For a smart home office with a Mac or MacBook centre stage, nothing else will slip in visually better than this drive. The silver aluminium is just like that of a MacBook shell. The dark grey provides the same two-tone contrast as a MacBook's keys. This is no accident.

The Seagate Fast SSD also has more interesting software than the competition. Rather than letting you encrypt the drive, Seagate Toolkit is used to specify folders the SSD will mirror. The most obvious use for this is to back up the folder in which you dump all the photos you take. We're thinking DSLR or CSC photos rather than those taken with your iPhone.

Seagate seems to think so too. As part of the package you get a two-month free trial to Adobe's Creative Cloud Photography plan. Anyone can get a one-month trial, but the Fast SSD saves you £20 for that second month.

Creative Cloud Photography includes access to Adobe Lightroom CC, Photoshop CC and 20GB of cloud storage. It's everything you need to edit photos, pro-style.

If you want a portable SSD you can chuck around and take everywhere without any worries, the SanDisk model may be a better pick. However, if it'll spend much of its life on a desk, this Seagate is a class act.

5. Samsung 860 Evo

Samsung 860 Evo

This SSD is our pick as the best for money savers.

If the prices of the portable SSDs above look far too high, the best solution is a standard 2.5in SSD drive. These are significantly cheaper at all capacities.

After a bargain? Lower-capacity Kingston Technology A400 drives are available cheaply online. However our current pick of 2.5in drives is the Samsung Evo 860. When used directly with a SATA interface you'll see speeds of up to 550MB/s.

However, we're not looking to bung an SSD into a Mac. We want a portable drive, so we need an extra accessory.

When you buy a Samsung 860 Eno, you get the drive in a cardboard box. That's it. To plug it into a MacBook we need either a SATA to USB cable or an enclosure.

We've tried both. Using a dirt-cheap SATA-to-USB cable from eBay, speeds were only around the 220MB/s mark. That's not even close to the Samsung 860 EVO's capabilities.

We saw much better results from the ADATA ED600. It's a largely plastic box for the SSD that plugs into its SATA connector, and has a microUSB 3.0 port on its back. The box has a rubber seal, upping the ruggedisation to IP54. And it means any drop damage will be to the cheap case, not the expensive SSD.

As this is only a USB 3.0 enclosure with 5Gbps bandwidth, speeds are lower than the USB 3.1 Gen 2 drives. We see read speeds of 420MB/s and writes of 427MB/s. You'll get better performance with a Gen 2-compatible enclosure. But the Samsung 860 Evo is our budget pick: let's keep things affordable.

Size is the more pressing difference. Even without an enclosure a 2.5in drive like this is significantly bigger than a 'dedicated' portable drive. It's only 6.8mm thick but the 100m by 70mm footprint is less pocket-friendly than the rest.

A little more prep is involved too. You'll need to format the drive using macOS's Disk Utility app on first connecting. It only takes a minute or two, but means the Samsung Evo 860 isn't 'plug and play'.

If money is no object and you want the most portable solution going, a drive like this may not be what you need. However, you can save up to 40 per cent of the cost.

The Samsung Evo 860 also comes with a great 5-year or 600TBW (500GB version) warranty. TBW stands for 'terabytes written', and offers a rough estimate of how much data can be put onto the drive before you might see some age-related issues. Samsung upped the TBW by a factor of eight with this generation, telling us the Evo 860 is likely to be a highly reliable SSD.

6. WD My Passport Wireless SSD

WD My Passport Wireless SSD

This SSD is our pick as the best for photographers.

If you've read the entries above, there are a few obvious conclusions. All current portable SSDs are radically faster than hard drives, but their speeds are also fairly similar. Which you should buy boils down to shape, design and ruggedisation.

Western Digital's My Passport Wireless SSD offers something completely different, though. This is a wireless SSD drive with an integrated battery, SD card reader and USB port.

It's far larger than any of the other drives here, including a 2.5in SSD with an enclosure. The My Passport Wireless SSD won't fit into any pockets.

However, it can do things other drives cannot. A photographer out in the field may find the My Passport more useful than any other.

For example, it can be set to auto back up any files stored on an inserted SD card or USB device. You could then use an iPad to review shots taken, more reliably than the Wi-Fi interfaces built into most DSLRs and CSCs we've tried, too. As the SSD creates its own wireless network, there's no need for an internet connection.

There's an app for iOS (and Android in case you're a mixed-platform user) that also lets you auto back up images from phones or tablet, and both transfer and download other files. You can even stream movies stored on the drive from the app on your iPad, although codec support is limited.

Ten-hour battery life makes these wireless file transfers of real use too. And an LED indicator on the drive offers a quick estimate of the remaining charge. It's a tablet-grade 6,700mAh cell that can also be used to charge your phone or tablet. But stick to phones to avoid torpedoing the drive's own longevity.

There's one obvious issue. Transfer speeds over Wi-Fi are not even close to those of the SSD drive inside. Files download at around 10MB/s. If wireless use is the main appeal and you don't need the shock-proofing of a solid state drive, you may be just as happy with the hard drive version of the My Passport Wireless. It's cheaper. We looked at it more closely in our best hard drives feature.

Performance with a wired connection isn't as good as that of the other drives tested here either. Western Digital's own claim is read speeds of "up to 390MB/s". We recorded read speeds of 332.9MB/s and writes of 315MB/s. While two to three times faster than a hard drive, that's only around two-thirds the performance of other "standard" portable SSDs.

We'd also feel less confident the WD My Passport Wireless SSD would just brush itself off after a 2m drop. However, it does have a thick rubber outer that will soak up much of the force of an impact. Just make sure this protective jacket is on if you take the drive out in the field.

Buying one also requires a little more thought than the others here. It has two personalities, as wireless and SSD speeds are so fundamentally different. Still, for specific use cases this is one of the best storage peripherals around, particularly for photographers who'd like to use their iPad, rather than a laptop, to review images while out on a shoot.