Want a speedy PC? Then an SSD is a must-have. The catch has always been the price: until quite recently, solid-state storage was so expensive that it was common to buy a modestly sized SSD, onto which you’d install Windows and your favourite apps and games, and use a secondary mechanical drive as bulk storage for your photos, videos and other data.
Happily, prices have been steadily dropping, and you can now get a 500GB SSD – big enough to hold all your programs and files – for around £200. That’s what we’ve focused on here; if you need more storage (or less) then all of these drives are available in a range of capacities, at prices that are generally in line with their size.
In short, whether you’re looking for a tiny, nippy drive or a big beast of a disk, there’s an SSD out there for you. Read on to find out how to choose, and which drives are our favourites.
How to choose the right SSD for you
Which form factor do I need?
Form factor is the shape and connection type used to hook up the SSD to your computer. There are two main physical shapes on the market: the traditional 2.5in drive, which is direct drop-in replacement for a hard drive, and the M.2 format. This latter type can reach much faster speeds than the older SATA standard: SATA is limited to around 500-550MB/sec read and write speed, whereas an M.2 drive using the latest NVMe technology can go ten times faster. Not all computers can use M.2 though – check whether your motherboard has the right slot.
How fast should it be?
Don’t worry too much about speed. Even the cheapest drives now offer adequate performance for Windows, games and programs to load in a matter of seconds. However, if you have a particular need for speed - think photographer or video editor – then there are a few measurements to consider. The first is sequential speed, which is how fast a drive can continually read or write data such as a single large video file – this is what counts for moving most files around. The second is random-access performance, which indicates how a drive will cope when lots of programs are demanding read and write operations at once. Here there are two figures to consider: raw throughput in MB/sec, and the absolute number of input/output operations per second, or IOPs.
Will it be reliable?
The final thing to think about is reliability. Even cheap drives generally come with three-year warranties but the more expensive ones are designed to last longer, and may offer five or even ten years. It’s not just about age, either: the NAND memory in SSDs degrades each time data is written to it, and a cheap drive might top out at 100TB of total written data, while pricier ones can quadruple that (these figures increase with higher-capacity drives). A word of warning, though: if your drive does fail before its time, the manufacturer should replace it, but your data will be lost forever – so always keep a backup.
How do SSDs work?
Unlike hard drives, which use magnets to store data on spinning metal disks, SSDs have no moving parts. Instead they use memory chips, similar to the RAM in your PC. The technology is known as NAND flash, and it comes in a few different forms. The most expensive chips store one bit of information – on or off (0,1) – in each memory cell, an arrangement called SLC (single-level cell).
Most modern NAND chips use an MLC (multi-level cell) approach, which lets them store two bits of data per cell. This obviously means you only need half as many cells, so it’s much more cost-effective – but it decreases write speed, and reduces the life of the cells. You can also get triple-level cells that store three bits of data per cell. The latest NAND from Samsung and Micron (Crucial) also has the memory cells stacked on top of each other, further increasing the data density of the memory and in turn reducing costs. This is known as 3D NAND.
To get around the performance limitations of multi-level cell chips, some drives use a certain number of SLC (typically around 10GB’s worth) as a high-speed write buffer. This keeps things feeling responsive, but once this is filled, write speed drops dramatically until the drive has a chance to flush out the buffer.
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The best SSDs to buy in 2018
1. Samsung 960 Evo: A fast SSD that doesn’t break the bank
Price: £212 (500GB) | Buy the Samsung 960 Evo now from Amazon
This M.2 SSD is blazing fast yet affordable – and it’s available in capacities up to 1TB, so it should be large enough for even power users.
When we say blazing fast, we mean it. In the CrystalDiskMark benchmark, the 500GB 960 Evo hit amazing speeds of 3,406MB/sec read and 1,766MB/sec write in the Q32 sequential test. It also managed read and write speeds of 1,197MB/sec and 701MB/sec respectively in the Q32 random-access test.
The 960 Evo is reliable too, despite being based on TLC NAND. Samsung claims a mean time between failures of 1.5 million hours, and the various capacities are warrantied for up to three years or for between 100TB and 400TB of total written data. Only the very most demanding users will need more.
The only question is whether you really need all this speed. For everyday computing, a SATA drive will feel very nearly as quick, and can be had in larger capacities at lower prices.
Key specs: Form Factor: M.2; Connection protocol: NVMe; Capacities: 250GB, 500GB, 1TB; Warranty: 3 years or up to 100TBW-400TBW; NAND type: TLC 3D NAND
2. Samsung 960 Pro M2: The fastest SSD around
Price: £272 (512GB) | Buy the Samsung 960 Pro M2 from Amazon
The Samsung 960 Pro is the fastest consumer SSD you can buy. And since it’s available in capacities up to 2TB, it’s big enough for almost anyone’s needs. You’ll need deep pockets if you’re considering that model, though: it costs an eye-watering £1100.
Still, performance can’t be beaten. CrystalDiskMark showed our 512GB drive delivering 3,566MB/sec sequential read and 2,007MB/sec sequential write. It aced the random-access test too, with read and write speeds of 1,376MB/sec and 1,401MB/sec.
A very slight disappointment is that the warranty is only five years long. That’s still a decent time period, and is on par with any other premium M.2 drive, it feels a bit mean when Samsung’s own 850 Pro SATA drives offer a decade-long warranty. Still, with total written data amounts of between 400TB and 1200TB, these drives are well set for a life of heavy-duty work. Quite simply, if you’re after the ultimate, this is the drive to get.
Key specs – Form Factor: M.2; Connection protocol: NVMe; Capacities: 512GB, 1TB, 2TB; Warranty: 5 years or up to 400TBW-1200TBW; NAND type: MLC 3D NAND
3. WD Blue 3D NAND: A great M.2 drive for those on a budget
Price: £127 (500GB) | Buy the WD Blue 3D NAND now from Amazon
The WD Blue 3D NAND is an M.2 drive, but it actually uses the SATA connection standard. That means it’s no faster than a SATA drive, but you get all the other advantages of M.2: it’s physically much smaller and neater, and it slots directly into your motherboard, so you don’t have to mess around with cables or find a place to mount the drive.
What’s more, it’s still perfectly capable when it comes to performance, delivering 560MB/sec sequential read, 533MB/sec sequential write, 385MB/sec random read and 284MB/sec random write in CrystalDiskMark. Note that this is a TLC drive, so there’s the caveat of reduced write performance if you’re writing huge amounts of data to it at once, but for most home users this shouldn’t be a concern.
The WD Blue SSD range comes with a three-year warranty and endurance ratings of 100 to 500TBW, making it an appealing choice that’s much cheaper than most M.2 drives. For those wedded to the more traditional form factors, it’s also available in a standard 2.5in SATA housing.
Key specs – Form Factor: M.2; Connection protocol: SATA; Capacities: 250GB, 500GB, 1TB, 2TB; Warranty: 3 years or up to 100TBW-500TBW; NAND type: TLC 3D NAND
4. Samsung 850 Evo: A great-value mid-range SSD
Price when reviewed: £127 (500GB) | Buy the Samsung 850 Evo now from Amazon
Samsung’s 850 Evo drive is a real bargain, thanks to the manufacturer’s 3D NAND technology, which keeps per-gigabyte costs to a minimum. It also comes in a great range of sizes, from 120GB all the way up to 4TB. You’ll be paying £1,300 for the latter, but at least the option’s there. What’s more, all models come with a five-year warranty, while many rivals only offer three.
Performance is impressive too. All the drives are rated for 540MB/sec sequential read and 520MB/sec sequential write, with between 94,000-98,000IOPs read and 88,000-90,000IOPs write for random operations.
As with all mid-range drives, you do get slightly slower write speeds thanks to the use of TLC NAND, but the drive uses a sizeable cache of MLC NAND to compensate for this. In everyday use it’s fast enough to saturate a SATA connection, so it’s unlikely you’ll ever notice a difference between this and much pricier SATA SSDs.
Simply put, for most people this SSD is the one to go for. Look elsewhere only if you definitely need more speed, desperately need to save money or prefer the smaller M.2 format.
Key specs – Form Factor: 2.5in SATA; Connection protocol: SATA; Capacities: 120GB, 250GB, 500GB, 1TB, 2TB, 4TB; Warranty: 5 years or up to 75TBW-300TBW; NAND type: TLC 3D NAND
5. Samsung 850 Pro: The fastest SATA SSD money can buy
Price: £190 (512GB) | Buy the Samsung 850 Pro now from Amazon
The 850 Pro is the faster brother to the 850 Evo - but its advantages are subtle. Thanks to the technical limitations of SATA, the 850 Pro’s read speeds are no faster than those of any other SATA SSD.
Rather, it shows its strength when it comes to sustained write performance. Where cheaper drives based on TLC NAND use a buffer to get a short burst of initial write speed, the 850 Pro can maintain its write speed almost indefinitely. This makes it ideal for really heavy duty, sustained workloads.
That’s backed up by a massive 10-year warranty, and the total amount of data that can be written to each drive is high too: the 256GB drive can cope with 150TB of data while the 2TB model can hit 450TB.
Not everyone needs this sort of heavy-duty drive: if you don’t then you can save a decent bit of money by choosing the Evo instead. But if you’re looking for a SATA drive that promises absolute reliability, high capacity options and the best speed the connection can give you, the 850 Pro is the one to get.
Key specs – Form Factor: 2.5in SATA; Connection protocol: SATA; Capacities: 256GB, 512GB, 1TB, 2TB; Warranty: 10 years or up to 150TBW-450TBW; NAND type: MLC 3D NAND
6. Crucial MX300: An excellent SATA SSD at a very tempting price
Price: £124 (525GB) | Buy the Crucial MX300 now from Amazon
Crucial’s MX300 SSDs are great value. In particular, the 275GB and 525GB models offer a nice 25GB capacity bump over most other comparable drives, without costing any extra.
Like Samsung, Crucial’s parent company Micron has achieved this by developing highly efficient 3D NAND chips. However, these don’t quite match the performance of Samsung’s design. We found the 525GB MX300 achieved a sequential read rate of just 496MB/sec, while the Samsung 850 Evo managed 540MB/sec. The Crucial drive also trailed in the 4K random read test, hitting just 28.6MB/sec, compared to around 40MB/sec for competing SATA SSDs.
For most home users, though, such comparisons are academic: the MX300 still represents a huge leap up in performance from a mechanical hard drive. If you’re looking to build a nippy PC with plenty of space, which will boot up, load games and transfer files nice and quickly, this one certainly deserves to be on your shortlist.
Key specs – Form Factor: 2.5in SATA; Connection protocol: SATA; Capacities: 275GB, 525GB, 1TB, 2TB; Warranty: 3 years or up to 80TBW-400TBW; NAND type: MLC 3D NAND