What is an SSD?
SSDs have become a necessity for systems and laptops. Modern processors can handle a huge amount of data and calculations at once, but they are often limited not only by the amount of RAM you have installed, but the type of storage you have in your system.
Previously systems would use hard drives (HDDs) as their primary storage. But hard drives are slow - due to platters that have to spin up to speed and an arm that reads and writes to them.
This means that SSDs, with their flash-based storage system, are far superior.
However, there are multiple different types of SSD. So, which one do you choose?
There are different physical sizes such as M.2 and 2.5” as well as different connection types such as SATA or PCIe. You can also choose from different capacities ranging from 120GB all the way up to 8TB.
We’ll go through all of these things (and more) below. Hopefully you’ll finish this article with a better idea of what SSD you should choose for your system.
Form factor and what your PC can support
Most solid state drives come in one of three different form factors, which we’ve explained in detail below.
Choosing an SSD first comes down to picking one of these three form factors. The majority of modern motherboards will support all three form factors, however we would always recommend checking with your motherboard manufacturer for support.
With that in mind, let’s take a look at each form factor.
M.2 SSDs are fast becoming the most popular form of SSD for two reasons; they can support PCIe NVMe connections (as well as SATA), making them extremely quick. They are also small and do not require any cabling, making them easy to install.
M.2 drives are available in different physical sizes, and are named based on their width and length.
All M.2 SSDs are 22mm wide, however they are available in different lengths of 30mm, 42mm, 60mm, 80mm and 110mm; so a 22mm wide, 80mm long M.2 SSD will be labelled as ‘M.2-2280’.
Whilst it’s possible to get SSDs in most of these sizes, by far and away the most popular size is 80mm.
M.2 SSDs are also the most popular type of drives for laptops as they take up much less space than HDD-size 2.5” SSD drives.
Before M.2 became popular, 2.5” was the standard SSD form factor. SSDs have been around for several years and almost every PC case made in the last decade will support mounting a 2.5” SSD.
Most laptops (especially older models) also have a 2.5” SSD bay. As a result, 2.5” SSDs became the go-to choice for people looking to upgrade their laptop’s hard drive to something much faster.
The disadvantage of 2.5” SSDs compared to their M.2 counterparts is that they use the SATA protocol which is slower than PCIe NVMe. In addition, installing a 2.5” SSD requires cabling from your system’s power supply as well as a cable going from the drive into your motherboard.
Add-in Card (AiC) SSDs
AiC SSDs fit into a spare PCI Express 3.0 slot (usually a x16 or x4) and use only PCIe for their connections, making them much faster than SATA based SSDs.
In fact, AiC SSDs can be faster than M.2 SSDs. This is because M.2 SSDs are limited to using four PCIe lanes, whereas AiC SSDs can use up to 16.
However, if you’re going to select an AiC SSD, you’ll have to make sure you have enough room in your system to accommodate it. If you’ve got a modern graphics card that takes up several slots worth of space in your system, you may not have room to fit an AiC SSD.
AiC SSDs are also generally more expensive than other types of SSD. This is because of the card’s form factor, which requires a heatsink to sustain the faster speeds.
What is SATA and PCIe?
SSD drives use different interfaces to connect to your computer; SATA and PCIe. These interfaces can limit how fast an SSD drive can be.
PCIe 3.0 x4 or PCIe 4.0 x4
PCIe is the fastest type of interface you’ll usually see, with PCIe 3.0 drives exhibiting read and write speeds around the 3,500MB/s range, whilst PCIe 4.0 drives exhibit read and write speeds up to a whopping 7,000MB/s.
Whilst you’ll need certain motherboards and processors to get PCIe 4.0 support, almost any modern motherboard and processor will support PCIe 3.0.
The SATA interface is limited to around 550MB/s so it’s generally much slower than a PCIe-based SSD.
That isn’t to say SATA is slow in itself. It’ll still be much, much faster than a hard drive, and for general use you likely won’t notice the difference between a SATA drive and a PCIe drive.
What capacity SSDs can you get?
You can buy SSDs in capacities all the way up to 8TB, although they start getting very expensive once you get past 1TB. You’ll see the following capacities available:
120GB or 128GB SSD
Whilst it might be tempting to get a low-capacity drive such as this to just install Windows and apps, it’s a poor choice. Not only is it very easy to run out of space quickly, but these drives have the slowest performance of all as they’ll only have a couple of flash modules on them.
240GB, 250GB or 256GB SSD
These are usually a fair bit quicker than the 120/128GB models, and are also large enough to handle Windows and applications with a decent amount of space for more files.
We would recommend these if you are on a tight budget - they’re not much more expensive than the lower capacity models, but if your budget can stretch a bit further, the 500GB range is the sweet spot.
480GB, 500GB or 512GB SSD
These drives are often a good balance between space and price.
You’ll have plenty of room for your operating system, applications, files, and even some games. 1TB pricing is starting to come down, so you may want to stretch your budget for more capacity, but for now we would recommend buying an SSD in the 480-512GB range.
960GB or 1TB SSD
Now available for under £100, these capacity SSDs are great if you need more room for your games without breaking the bank.
Whilst some people may be tempted to go for a lower-capacity SSD and then add a hard drive, the performance from the hard drive would be nowhere near what you’d get from an SSD of this capacity.
At this capacity you’re currently looking at at least £180 for a drive. An SSD of this capacity is only really useful if you’re doing something like video editing (and need a large scratch drive), or doing lots of gaming across multiple games and don’t want to keep having to delete and install to make room on your system.
4TB or higher SSD
These are truly expensive, starting at over £330. In all honesty, these are only worth purchasing if your workflow requires such a large amount of fast storage, otherwise you should certainly buy an SSD with a smaller capacity.
What’s the best SSD for you?
Now you know what the different form factors, capacities and connections are, which SSD should you choose?
Firstly, think about how much space you need. As we mentioned above, we’d recommend somewhere around 500GB (or even 1TB if your budget allows), with a minimum of around 250GB.
Next, you need to think about form factor. If your motherboard or device can support an M.2 drive then that’s the one we would recommend; it’s the easiest type of drive to install, and based on the interface you choose, can also be the fastest.
If you don’t have an M.2 slot (or it’s already in use), then you should choose the standard 2.5” size - the AiC form factor will get you faster speeds but is very expensive and only worthwhile if you’re building a dedicated workstation machine.
Finally, you need to choose the interface. If you’re running an M.2 drive we’d recommend at least PCIe 3.0 x4 NVMe.
It’s not necessary to go for PCIe 4.0, even if you have the hardware to support it - it’s generally aimed at enthusiasts or workers who need a high amount of throughput. For most use cases, you wouldn’t be able to tell the difference between PCIe 3.0 and PCIe 4.0.
If you’re going for the 2.5” form factor, you’re stuck with SATA, but don’t worry - compared to a hard drive it’ll still be very fast!
Hopefully you now know the main points you need to think about when choosing an SSD for your computer.
There’s lots more to SSDs than what’s detailed above - such as Random IOPS, Endurance, NAND types and more - but we will discuss these things in a separate article.
But, for now, this article should help you choose a great SSD for your system that will improve its performance massively over any hard drive.