If there’s one constant in computing, it’s that we’ll always need more storage. If there’s a second, it’s that the faster it is the better. Currently, the best storage option on both fronts is an M.2 SSD drive. If the move from mechanical drives to solid state was a step forward, then the move from 2.5in SSDs to M.2 has been a staggering leap in terms of performance and efficiency, and the technology continues to improve.
Mostly ditching the old SATA interface, which was designed for hard disks, M.2 drives primarily run using PCI Express, delivering speeds that seemed impossible a few years ago.
What’s more, M.2 drives combine power and data in one connector, so there’s less cable clutter in your PC and, as the drives plug directly into a socket on your motherboard, you can get away with a smaller case. That’s great news for anyone who’s fancied a mini PC but has been put off by the restrictive number of drive bays.
In this Labs test, we’ve got 14 of the latest M.2 drives, ranging from budget models up to the latest Gen 4 drives (also written as PCI-E 4.0 and PCIe 4.0) with the fastest speeds. What about SATA drives, you ask? Well, we’ve hit the limit of what these drives are capable of, and there are no new releases worth noting, so we’ve retested some of the drives from previous reviews..
How to choose the perfect M.2 SSD for you
Only fools rush into spending hundreds of pounds on storage. We set out 10 questions you must ask yourself before you spend a single cent.
1 Do I want an internal or external drive?
We’ve reviewed internal drives here, although with an external adapter you can use a USB drive instead. While USB 3.2 Gen 2 speeds are considerably faster than previous generations, they’re not as quick as internal drives by a long shot. USB 3.2 Gen 2 2x1 runs at up to 10Gbits/sec, which works out at around 1,250MB/sec, a fraction of the maximum speeds of the latest SSDs. So why bother?
External drives are useful if you need to move data from one computer to another, or you want to take a secure backup of files, storing the drive in a different location or even a safe. External drives are also useful for devices that are hard to upgrade, such as laptops.
There’s a big disadvantage: files on an external drive aren’t accessible if the drive’s not connected. That makes external drives largely unsuitable for storing apps or files you often need.
2 Should I get an SSD or a mechanical drive?
It’s staggering to see mechanical hard disks still available. Their main advantage is that they’re cheaper than their SSD equivalent, particularly in larger sizes. So, does overall size trump the speed and quality advantages of SSDs? In most cases, no.
Mechanical disks can be helpful if you have an older device that needs one, such as a NAS drive. If, for example, you’re running an existing NAS and one hard disk fails, you’ll need to replace it with the same. Otherwise, you should buy solid-state storage instead, be that an M.2 drive or even an older SATA drive.
3 What about SATA drives?
Talking about Serial ATA (SATA), are those drives still worth buying? The simple answer is no. SATA was designed in the time of mechanical hard disks, and tops out at speeds of around 600MB/sec – that’s pretty slow in terms of today’s storage.
The first SSDs used the SATA interface in a 2.5in format, because they had to utilise an existing storage connector. Today, M.2 drives are, for the most part, designed to be used with PCI Express, so there’s very little point in buying an older SATA-based drive, mechanical or solid state.
The only exception is if you’ve maxed out your M.2 slots and need to add additional storage, with only 2.5in drive bays free in your PC. A SATA SSD is then a better choice than a mechanical hard disk.
4 Are all M.2 drives the same?
Not quite. M.2 is the name of the slot, not the interface. M.2 slots can take SATA drives, running just as slowly as they would when connected via a SATA cable, but they can also run NVMe (Non-Volatile Memory express) drives. NVMe is a communications protocol designed for solid-state storage, built to deliver the fastest speeds.
NVMe uses PCI Express, of which the two current generations are PCI-E Gen3 and PCI-E Gen4 (also written PCI-E 4.0 and PCIe 4.0). The main difference between the two is in the speeds they provide. PCI Gen3 runs at 1,000MB/sec per lane, while PCI-E Gen4 doubles that to 2,000MB/sec. With most storage slots offering up to four lanes, that means that PCI-E Gen3 runs at up to 4,000MB/sec and PCI-E Gen4 up to 8,000MB/sec.
Support for PCI-E 4.0 depends on your processor and motherboard. At the minimum, you need a processor that supports PCI-E 4.0. It’s then essential to have a motherboard that supports the technology.
You may find support is mixed, even on the same motherboard. For example, with a Ryzen 5 5000 series processor and B550 motherboard, one M.2 slot is controlled by the CPU and runs at up to PCI-E Gen4 speeds; the other slot is controlled by the chipset and runs at up to PCI-E Gen3 speeds.
Before you buy, check what slots you have and the speeds they run at, and what speeds your CPU supports. Unless you’re planning an upgrade soon and will keep the storage, it’s not worth paying extra for a PCI-E Gen4 SSD if it goes in a PCI-E Gen3 slot. While this will work, you’ll be massively limiting the drive’s speed.
5 Can I mix M.2 drives and SATA drives?
You can, although again, you’ll need to do some research. In most cases, an M.2 slot will share a SATA
