What is an SSD?

Find out how solid-state drives work and why they’re overtaking traditional hard disk drives.

Understanding SSDs

You might have heard of an “SSD” before, but you’re not quite sure what it means. Our lives revolve around phones and computers now more than ever, so it’s good to know about the hardware that keeps things running behind the scenes. These days, SSDs are an important component of every smartphone, and of many new laptops and computers, quickly overtaking HDDs (hard disk drives) as the preferred tech for primary computer storage.

Whether you’re building or upgrading your own PC or you’re simply looking for the best data storage solution for your laptop, it’s important to understand the difference between SSD and HDD and what alternatives exist for both.

What does SSD stand for?

SSD stands for solid-state drive. A solid-state drive is a newer alternative to hard disk drives (HDDs), which have been around since the 1950s.

What is a solid-state drive?

An SSD is a digital storage device that first emerged at a consumer level in the 1990s. It is used with computers, phones, and tablets.

What is SSD storage used for?

Every computer has a hard drive that is used to store data on a long-term basis. Any file you create or download on your computer is saved to the computer’s hard drive. This type of storage technology is known as secondary storage, while a computer’s RAM (Random Access Memory) is known as its primary storage.

An SSD is a type of secondary storage, so it’s used for storing personal data, like pictures, videos, music, and documents. In a computer, the SSD also stores the operating system code, frameworks, and drivers that allow the system to boot up and operate.

You can store the same data on an SSD that you could an HDD, but they differ in the way that data is stored.

These days, you’ll find SSDs are the preferred storage type on many high-end laptops, including all Apple laptops, and are becoming the standard on new PCs as well. Types of SSD are also used in all smartphones and tablets, though these aren’t completely identical to the hardware used in a computer’s SSD.


While they perform the same function, HDDs and SSDs operate in very different ways. To put it simply, HDDs are mechanical and use magnetic fields to run, while SDDs are electrical and use electrical currents to run.

How do HDDs work?

The traditional hard disk drive has been around since 1956, and while it has evolved greatly since then, the technology at its core remains the same.

A hard disk drive is made up of a stack of metal disks called platters that spin at rapid speeds. Each spinning disk contains trillions of tiny fragments that can be magnetized in order to represent bits. An actuator arm with a read/write head is able to scan the spinning platters and magnetize fragments in order to write information onto the hard drive, or detect magnetic charge to read the hard drive.

The magnetic charge of a fragment on a platter determines whether it represents a 0 or a 1 in binary code. The faster a platter can spin, the faster your computer can read and write data from or on your hard drive, and the more data contained on the hard drive, the longer it will take to access information.

One of the biggest disadvantages of HDDs is that because they have so many moving parts, they’re a lot more vulnerable to damage. It can be easy to damage HDDs if they’re mishandled, and laptops, in particular, are quite susceptible to these risks.

Furthermore, because the read/write head must locate the correct fragment on a platter before the computer can read or write any data, HDDs tend to work a lot slower than SSDs, which don’t rely on any moving parts. HDDs are also heavier and consume more energy than SSDs.

How do SSDs work?

HDDs were a groundbreaking solution at a time where digital tech was still developing, however as technology has evolved, newer and more efficient means have emerged, and SSDs are the perfect example.

Solid-state drives operate using NAND technology, which is a type of flash memory. NAND flash memory is non-volatile memory, meaning it does not need to be continuously powered to store and retain data.

Doing away with disks and magnets, an SSD is covered in trillions of interconnected flash memory cells that can store data. These flash cells house transistors that can be switched on or off. Like the magnetic charge of a fragment for HDDs, the electrical charge of a transistor on SSDs is used to represent 1s and 0s in binary. Think of flash memory chips as large grids of light switches. Whether a switch is on or off will determine whether it represents a 1 or a 0, which a computer will then be able to understand and translate into what we see on screen.

The interface of an SSD is purely electronic, but it can still store data when it isn’t powered. A metal-oxide semiconductor is used to provide the extra charge needed to retain the data after power is shut off, and this semiconductor is called a floating-gate transistor (FGT).

Because electricity travels so rapidly, SSD doesn’t need to wait or search for data like the read/write heads of an HDD must do, an SSD can access data instantaneously. Without all of the moving parts, SSDs are able to work quicker and stay cooler than the traditional hard drive.

Their sturdiness is especially advantageous in laptops, tablets, and phones, which are much more likely to experience shock than a big PC.

Drawbacks of using an SSD

SSDs don’t yet offer the same large capacity as HDDs, at least not in the same price range. The highest possible capacity for an HDD is 20TB, and while you can find SSDs that exceed this, SSDs are significantly more expensive to manufacture, and therefore buy. Prices for SSDs begin to spike once you’re looking at capacities above 4TB.

The longevity of SSDs is often determined by the amount data stored on them over time. The smaller storage capacity of SSDs may mean users find themselves frequently deleting old files to make room for new ones. But this just increases the total number of terabytes written and will wear out the drive faster.

To combat this, users are encouraged not to store media on SSD because it can take up a lot of space, and speed improvements aren’t as noticeable. The benefit of SSDs can be felt most when they are used to store operating systems, games, and programs as boot time speeds are reduced, and programs can open much faster.

This makes a cloud storage solution like Dropbox the perfect partner for an SSD. Dropbox is able to store the media files that otherwise may not fit on your drive and which would shorten its life span if they did. Freeing it of this task will allow you to make the most of your SSD.

Should I use an SSD?

Using an SSD instead of, or alongside a HDD, will have immediately obvious benefits for most users, and it is often cited as one of the most noticeable upgrades you can give your computer.

SSDs are especially attractive to gamers because of their faster loading times and because they use less energy, meaning they run cooler, which is a big advantage for running games. Any heavy gamer looking to build their own PC would benefit hugely from opting for an SSD.

Even if you’re not a gamer, upgrading an older PC’s hard drive to an SSD would likely result in significant improvement in its performance. Unfortunately, if you rely on your computer for document, video or photo storage, saving media on your SSD may hinder its performance in the long run, as SSDs slow down as they fill up. To enjoy the best of both worlds, consider storing your media files with Dropbox and let your SSD focus on what it does best.