Data is omnipresent. It’s stored on different devices — traditionally on a desktop PC, but now perhaps even more importantly on a mobile device such as a smartphone or tablet.
Even though data and system backups are often automated via the cloud, especially on mobile devices, you often feel more comfortable if you still have a tangible medium in your hand on which to store your digital treasures.
What’s more, sometimes you just want to move data from A to B quickly and easily. Or simply be available offline. Or move it directly to a storage medium to free up internal hard drive space.
Further reading: The best external drives
There is portable storage for all purposes. But there is no one solution for all applications.
This guide summarizes the most important advantages and disadvantages of external SSDs, HDDs, and USB sticks to make it easier for you to decide on the best portable drive.
External SATA SSD: All-round storage for everyday use
Internal SSDs with a SATA connection are now outdated and less common. However, they remain justifiably popular as external drives.
The reason: With a bandwidth of 6 Gbit/s, SATA delivers a theoretical transfer speed of up to 560 MB/s read and 530 MB/s write.
These values exceed the transfer rates of the widely used external interface USB 3.2 Gen1 (formerly USB 3.0), which is up to 500 MB/s, at least in theory.
This makes external drives in 2.5-inch format still a competitive storage solution for everyday PC use.
A SATA SSD that is no longer required can easily be reused as an external drive in an external housing. Installation is uncomplicated. In addition to USB-A, Type-C is also gaining ground as a PC connection.
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Advantages: In principle, the SATA drives in the external housings also have the advantages of all flash storage devices. They can read and write very quickly, especially with many small files.
And this pays off in everyday use. Low latency and short access times to small blocks of data randomly distributed on the drive are what count here. That’s why extensive programs can be started quickly from an external 2.5-inch hard drive or large photo collections can be opened without delay.
In addition to the speed, external SATA drives also benefit from the silent operation of the flash memory — as is generally the case with flash, only stationary parts are used.
In contrast to HDDs, SSDs are insensitive to shocks. Depending on the housing design, external SSDs can even withstand drops from a height of several feet without damage.
And there is another advantage of SATA SSDs that is worth mentioning: If you have removed the drive from the computer for a capacity upgrade, you can continue to use it as an external SSD without any problems.
All you need is an external housing in which to install the used drive. Inexpensive models in 2.5-inch format are available from around $10 — for example from Delock, Ugreen or Verbatim.
Further reading: Best external SSDs for gaming
At this price, the enclosures usually come with a USB 3.0 interface. If the enclosure is to be equipped with a USB Type-C port, prices start at around $20 — which is also not too high a hurdle.
Disadvantages: The SATA connection is on the decline for SSDs. At the same time, the interface is no longer being developed further. Higher transfer speeds are therefore not to be expected with SATA.
As a result, the choice of models is decreasing. An external SSD in 2.5-inch size, such as the Lexar SL200 model, costs around $90 with a capacity of 512GB and is therefore a manageable investment.
At higher capacities you will not usually find details of the flash type used. For this capacity, assume QLC (Quadruple Level Cell) flash modules, which store four bits per cell. They are intended for high capacities when maximum write speed is not important.
An example of an external 8TB SSD can be found in the Samsung Portable SSD T5 Evo. At $525, it’s not exactly a bargain. The price is put into perspective, because at around 7 cents per GB, it achieves a very fair result.
At 8TB, the Samsung Portable SSD T5 offers the maximum capacity of mobile SSDs with internal SATA technology. It comes into question when a lot of storage space is the top priority.
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Most mobile 2.5-inch SSDs have a capacity of 1 or 2TB. TLC (Triple Level Cell) flash memory can also be used here. It stores three bits per cell. These mobile storage devices are priced at around $70 for 1TB and $130 for 2TB. This results in prices per GB of between 6.5 and 7 cents.
External NVMe SSD: Lots of mobility and high speed
Ultra-mobile SSDs now make up the majority of external SSDs. The housings contain an NVMe drive that was originally intended for the M.2 slot.
These SSDs have a card shape — mostly 22 millimeters wide and 80 millimeters long. This is why you will also find them labelled 2280 if you are looking for an internal drive.
Further reading: Is USB or Thunderbolt better for portable SSDs? The key differences, explained
Advantages: Thanks to their compactness, many external NVMe SSDs are only slightly larger than a USB stick. This means they are very light and can fit into any bag. This is ideal if you need an external SSD for travelling.
External NVMe SSDs use USB-C as a connector throughout. It is twist-proof and therefore cannot be plugged into the port the wrong way round.
The majority of models use USB 3.2 Gen2 as the standard with a transfer speed of 10Gbit per second.
Sequentially, data rates of around 1,000MB/s can be achieved for both reading and writing. This makes them approximately twice as fast as external SATA SSDs.
The increase in speed is noticeable with every copying process. Regardless of whether you are writing and reading many small or very large files, the work is done quickly.
This is why external NVMe SSDs are recommended both for quick file copies in between and for extensive weekly backups.
As a rule, you can use external NVMe SSDs across all devices. This is because most of them are formatted in the exFAT file system. It can be used with Windows and Mac OS as well as with the Android and iOS mobile phone operating systems.
Some external NVMe SSDs are even explicitly designed for use with mobile devices. They are designed to relieve the internal memory or make extensive media content available at any time.
For example, you can take high-resolution photos and videos with your mobile phone camera and store them directly on the external data storage device. In this way, they can also be easily transferred to PCs and laptops.
One example is the Lexar ES4 Portable SSD model, where the external SSD can be attached to the back of the smartphone using a magnet. This means it doesn’t get in the way during use.
As with the external SSDs with SATA technology, the maximum possible capacity is 8TB. You no longer have to pay a high surcharge for the smaller and faster mobile drive.
An 8TB model such as the Sandisk Extreme Portable SSD costs around $600. As with the 2.5-inch variants, the price per GB is 7 cents.
External NVMe SSDs are available with different capacities. They usually start at 500GB, for which an average of $80 is currently due. This results in a comparatively high 16 cents per GB.
Most models are available with 1 and 2TB capacity. In the cheapest case, you pay around $70 (1TB) or $110 (2TB) or between 7 and 6 cents. The latter applies to the 2TB version, which is the best value for money.
NVMe SSDs with cutting-edge USB interfaces such as the Adata SE920 with USB4 must ensure good heat dissipation if data transfers are not to be throttled due to the heat. This comes at the expense of compactness.
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You usually have to pay a little more for extras such as rubber coating, drop protection, or protection against moisture. Additional programs such as those for assigning a password or for SSD maintenance, on the other hand, are usually included free of charge.
They are either included directly on the drive or can be downloaded from the manufacturer’s website.
Disadvantages: NVMe SSDs are often so small that they can easily get lost. Small cut-outs on the housings are designed to prevent this, as they can be attached to something else — such as a bag.
As only Type-C is provided as a connection, you need an adapter or adapter cable to connect to USB-A interfaces. The accessories are usually, but not always, included in the box.
The speed advantage is lost when connected to older USB interfaces. Data transfer drops to the level of the connected type A interface. With USB 3.0 (USB 3.2 Gen1) to around 500MB/s, with USB 2.0 even to a maximum of only 50MB/s.
Some external NVMe SSDs, such as the Sandisk Extreme Portable SSD, are available in many different capacities. Additional data protection is provided by rubber coating and insulation against moisture.
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Speaking of USB: External NVMe SSDs are available in many USB standards. These now include USB 3.2 Gen2x2 with 20Gbit/s, USB4 with 40Gbit/s, USB4.2 with 80Gbit/s, and Thunderbolt as TB 3 and TB 4 with 40Gbit/s and TB 5 with 80Gbit/s.
The variety often leads to confusion, as you need to know about the standardizations to avoid making the wrong purchase.
The faster the data transfer, the more heat is generated. This is why the fast NVMe SSDs can get very hot. In the worst case, this harbors the risk of data loss. Enclosures with ventilation slots and even built-in mini fans are designed to counteract this.
However, they come at the expense of compactness and are reflected in higher prices.
A cutting-edge USB4 model — for example from the Adata SE920 series — costs a good 10 cents per GB for the 1TB version.
USB stick: Perfect for short-term storage activities
The most mobile form of external storage is the USB stick. It can even be the size of a thumbnail and still offer space for lots of data. USB sticks differ in terms of capacity and interfaces.
Basically, it must be clear: The flash components used in USB sticks are not of the highest quality.
Advantages: USB sticks are at the top in terms of mobility. They are designed from the outset to transport data stored on them from one computer to another. The emphasis is on transport, not on long-term storage of data.
There are model variants of USB sticks that have two different USB interfaces — in addition to USB-A, there is also the twist-proof type C connector. With dual sticks, you save on extra adapter solutions.
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With sticks, you can find models that are equipped with both USB A and C interfaces. This saves you adapter solutions if you often need to exchange data between older and newer computers.
You can find these USB sticks under terms such as “dual drive” or “dual stick,” such as the Verbatim Dual Quick Stick models, which are available in capacities from 128GB to 1TB.
Disadvantages: The cheaper the USB flash drives on offer, the more skepticism is required. Even with a stick with a type C connection, the data transfer speed can drop to an outdated USB 2.0 level.
In many cases, there is no precise information on the packaging. If you need a fast stick, look out for information such as USB 3.2 Gen2 or data transfer speeds of up to 1,000MB/s.
Cheap sticks from brand manufacturers cost around 7 cents per GB. If an offer is significantly lower, caution is advised. It may be a counterfeit.
In this case, the specified capacity is usually incorrect. In addition, the quality of the flash modules or the controller chip may be poor. It’s likely the modules will soon fail and the stick will quickly become unusable.
The size of a USB stick can have an impact on data security. Very small USB sticks usually have poorer heat dissipation than larger versions. In addition, mini housings are often less robust. They are less resistant to frequent plugging and unplugging than larger sticks.
External HDDs: Still used for backups and archiving
Even though the competition from SSDs is putting pressure on HDDs, magnetic hard drives remain useful as mass storage devices in external enclosures and NAS systems. Both 2.5 and 3.5 inch HDD designs can be installed inside. SATA III is always used as the internal connection.
External HDDs in 3.5-inch format are capacity wonders with 24TB to even 26TB. At the same time, the price per GB is unbeatably favorable. However, these storage devices are not designed to be taken away, but for stationary use.
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Advantages: External HDDs are capacity monsters. Currently, the maximum storage capacity of mobile 3.5-inch HDDs is 28TB. Such storage monsters are primarily intended for professional use — such as Seagate Expansion Desktop drives.
At a price of less than $400, you can see what incredible value a high-capacity external HDD be can be.
In most cases, this will be sufficient for home use. Prices per GB of around 2 cents are not unusual here — for example, the Seagate Expansion 8TB desktop hard drive for $150.
An external drive with a 2.5-inch magnetic hard drive usually has a maximum capacity of 5TB. You can get a 4TB drive for less than $110 — for example from Toshiba’s Canvio Basic series. This results in extremely favorable prices of around 3 cents per GB.
Further reading: How to turn any SSD into a DIY external drive
Both external HDD variants are perfect if you want to create regular backups where reliability is more important than the fastest mode of operation.
NAS HDDs are a special form here: They are designed for continuous operation in network storage. Thanks to customized firmware, they tolerate many simultaneous accesses from several client PCs better than desktop hard drives.
They also react less sensitively to vibrations — this is important because they are often used in a raid network with several hard drives.
NAS are special forms of external storage. They make data available to several clients in the network. As they need to be constantly accessible, they require HDDs that are designed for continuous operation.
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Disadvantages: Due to their design with disks and mechanical components such as read/write heads, HDDs generally tolerate shocks and drops much worse than SSDs.
As external drives, they are also relatively heavy. This is why only the 2.5-inch variants are actually suitable for carrying around. An external HDD in 3.5-inch format also requires an external power supply unit to ensure that the power supply works — this alone speaks against mobile use.
Not every NAS hard drive can be used in network storage. Before you decide on a specific model, you need to check the compatibility lists of the respective NAS device manufacturer.
To do this, search the website for your exact NAS product designation and also check the desired capacity. Even in this respect, not all NAS hard drives pass the compatibility tests.
This article originally appeared on our sister publication PC-WELT and was translated and localized from German.
