How to Choose an External Hard Drive

Buy an external hard drive, but don’t know which one yet? This article can read what to look out for when buying an external hard drive (HDD) or external SSD.

To make a choice easier, I mention in this article all the important features that you can pay attention to when buying an external hard drive.


How to choose an external hard drive | Things to Consider Before Buying External Hard Drive

Things to Consider Before Buying External Hard Drive

Why buy an external hard drive? External vs internal hard drive

Do you want extra storage space? Then you can choose from an internal or an external hard drive.

An external hard drive is built into housing with one or more USB connections. With a USB cable, you can connect the external hard drive to any device with a USB input.

That’s why you can connect it to almost any laptop, PC, TV, smartphone, or tablet. That makes an external hard drive versatile in use.

Also, an external hard drive has an advantage over an internal hard drive for an easy exchange or transfer of data. Meanwhile, there are also external hard drives of small size, which are therefore very suitable for carrying.

While external hard drives will be a lot bigger than a USB stick, most external hard drives also have much higher storage capacity.

You can build an internal hard drive into your laptop or PC, and it is directly connected to a SATA connection here. An internal hard drive is only a better choice if you only want to use it in one laptop or PC to expand storage capacity.

The installation’s main advantage is that this is a neater solution; you do not need external devices for additional storage capacity. However, you will have to install/install the internal hard drive. If your PC or laptop has room for just one internal hard drive, you will also transfer the operating system and files from the original hard drive.


Drive type – external HDD or SSD?

There are two different types of external harddrives’; the HDD and the SSD. Below is the explanation of these two types.

The term HDD stands forHard Disk Drive’. The files are stored on disks, which have to rotate around to be read or described.

The advantage of an HDD is the low price compared to an SSD. You will also find a higher maximum storage capacity with HDDs. The largest external HDD has a storage capacity of up to 12TB (12000GB).

The main disadvantage of HDDs is that they are less fast than SSDs. Another (small) disadvantage of the HDD is that the rotating drives can produce a little bit of sound.

The term SSD stands for ‘Solid-State Drive’. Files are stored in an SSD, not on disks but memory chips. ‘Solid State’ means no moving parts, as with an HDD (Hard Disk Drive). Because an SSD does not consist of drives, the term ‘hard drive’ is actually incorrect for SSDs.

The biggest advantage of an SSD is the speed. If you often need to transfer many files between different devices, then an external SSD is the best choice as this will save you a lot of time. Because an external SSD does not contain running disks, it is also quieter.

An external SSD disadvantage is that they are a lot more expensive for the same amount of storage capacity. In terms of storage capacity, the largest SSDs are also smaller than HDDs.


How fast is the external hard drive? Read and write speed (MB/s)

The speed of an external hard drive is an important feature. The speed of external hard drives is mainly expressed in MB/s. Two different values are specified; the reading speed and the writing speed.

The hard drive’s read speed is the speed at which files that are already on the hard drive can be read. When using (opening) a file on the hard drive, it is readout. With typical usage such as loading a Word file or playing an audio or video file on the hard drive, this speed doesn’t really matter. However, the hard drive’s read speed matters when you want to transfer files from the external hard drive to another drive.

The write is the speed at which new files can be stored on the external hard drive. This write speed is important if you often transfer files to the external hard drive, for example, when backing up.

Manufacturers often specify the maximum reading and writing speed. Because these values only apply under optimal conditions, they are often higher than you can really expect.

If the speed is an important feature for you, then you better assume so-called benchmarks. When benchmarking a hard drive, a program measures the speed in multiple test scenarios. On a site like, consumers can test their hardware, and you can find the results. By looking at the average score of a particular product, you get a better idea of what to expect in practice.

Fast external HDDs have a read and write speed of about 100 MB/s. Fast external SSDs are about 5 times faster and often have read and write speeds around 500 MB/s.

HDDs often also mention the drive’s RPM, the number of rounds the disc rotates per minute. Common numbers are 5400 RPM and 7200 RPM. RPM is one of the factors that can affect reading and writing speed. Still, there are 5400 RPM drives with a higher read and write speed than 7200 RPM drives. Also, drives with high RPM have another disadvantage; they often make more noise.


Connection – USB 2.0, 3.0, 3.1? Type A or Type C (for Mac)?

To connect the external hard drive to your computer, a USB cable is usually used.

Most USB inputs on laptops and PCs are USB type A or USB-A, with a rectangular connection. Some new laptops (many Macs), smartphones and tablets use USB type C or USB-C. This is an oval connection.

When buying an external hard drive, make sure you have these cables with the right connection for your laptop or PC. This way, you avoid having to order additional cables or an adapter yourself.

In addition to the shape of the connection, the USB version is important. The most common versions are USB 2.0, 3.0 and 3.1. The later the version, the higher the maximum speed of file transfer.

Only using USB 2.0 will limit the transfer speed of an external hard drive. If you use USB 2.0, you will practically never reach more than 40-50 MB/s reading and writing speed.

Almost all hard drives have a USB 3.0 or 3.1 output and also come with a suitable USB cable. When connecting the external hard drive, make sure that you prefer to connect it to a USB 3.0 or USB 3.1 port. Many computers still have USB 2.0 connections because they are still perfectly suitable for connecting a mouse or keyboard. The piece of blue plastic can recognize a USB 3.0 or 3.1 port in the connection.


Disk size – 2.5 inches or 3.5 inches?

There are two standard dimensions or form factors used on external hard drives: 2.5 inches and 3.5 inches. External HDDs are available in both sizes, SSDs only in 2.5 inches. The advantage of the 2.5-inch version is that it is more portable due to its dimensions and weight. The highest storage capacity of a 2.5 inch HDD is currently 4TB.

Do you want an external HDD with as much storage space as possible? For example, 6 or 8 TB? Then you come to the 3.5 inch external hard drives.


Does the external hard drive need a power adapter?

Small external hard drives have enough power supply via USB. Larger hard drives that don’t have enough of this come with a power adapter.

Most 2.5-inch external hard drives don’t need a power adapter. Do you want to use the external hard drive to exchange files between different devices, often take them with you, or use the mobile? Then this type is the best choice.

Most 3.5-inch hard drives need a power adapter. To use these hard drives, you need access to a power outlet. Therefore, this type is not the best option for mobile use; you will always depend on a power outlet, and in addition to the external hard drive itself, you will also need to bring the power adapter.

Do you want to use the external hard drive only at home for backups, and is a large amount of storage important? Then a 3.5-inch hard drive with a power adapter is a good choice.


The price – price per GB or price-performance ratio

Do you want to use the external hard drive mainly for backup purposes? And does the maximum speed matter less to you? Then you can look at the best price per amount of storage capacity. Check out the list of cheapest hard drives in price per GB: cheap external hard drives – top 3.

Do you often need to transfer files? Then a fast hard drive will save you a lot of time. You will then have to weigh up how much you have left to the fastest possible external hard drive.

External SSDs are much faster than external HDDs (about 5 times faster) and currently between 3 and 4 times more expensive for the same storage capacity. This does give external SSDs a better price-performance ratio than external HDDs.


Tip: internal hard drive + hard drive housing = external hard drive

Finally, a tip; you can also convert many internal hard drives (HDD) or internal SSDs into an external hard drive. You can build it into a hard drive housing.

So if you have an internal hard drive left, all you need is a case to turn this into an external hard drive. An external hard drive housing has a SATA connector on the inside, to which you connect the internal hard drive. Furthermore, the housing contains a chip that converts the SATA signal to USB.

Price 2.5″

hard drive housing

The case has a USB port on the outside so that you can connect the USB hard drive to your laptop, PC or other electronic devices. An internal hard drive in a case also works the same as a normal external hard drive.

These enclosures are available in 2.5 inches and 3.5 inches in size. The 3.5-inch external enclosures also have a power supply; large hard drives need more power than can be supplied over USB.

Sometimes it is possible to find an internal HDD and a hard drive housing that are cheaper than an external HDD. An internal SSD in a 2.5-inch housing is almost always considerably cheaper than an external SSD at the moment.

You already have a 2.5 inch hard drive housing for €13,95. A good 3.5 inch hard drive housing with a power adapter you already have for €27,95. Next, check out the cheapest SSDs, or the cheapest (internal) hard drives, and see if you’re out cheaper.

Questions or comments?

Do you have any questions about buying an external hard drive? Comments on the content of the article? Please leave a message below!

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I am tech writer who is passionate about technology and spearheads the core writing team on tech news

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