Is your PC so slow that you have to go make yourself a drink while it starts? Do you have to install software and updates during lunchtimes because it takes so long?

If you’re still using a traditional spinning disc hard drive (HDD), which has very slow read and write times, it is likely a bottleneck for your operating system and software.

Upgrading to a solid state hard drive (SSD), which stores data on flash memory and has no moving parts, can read and write many times faster than an HDD. An SSD is not subject to the mechanical failures of an HDD, is lighter, quieter and consumes less power.

Watch as we demonstrate the speed differences between 4 types of hard drive during Windows 10 installation, first start, and typical software installation. There is also a CrystalDiskMark benchmark for read/write comparison.

To help you decide which SSD is best for your computer, watch this video and read the detailed guide below.

How to buy the right SSD by


If you already know all about the specific drive types and want specific recommendations, check out our Best SSDs page. But if you don't have a Ph.D in SSD, here are a few things you need to consider when shopping.

Here are four quick tips, followed by our detailed answers to many FAQs:

Know your home computer: Find out if you have slots for M.2 drives on your motherboard and room in the chassis. If not, you may may need a 2.5-inch drive instead.
250 - 512GB capacity: Don't even consider buying a drive that has less than 256GB of storage. 500GB offers a good balance between price and capacity.
SATA is cheaper but slower: If your computer supports NVMe PCIe or Optane drives, consider buying a drive with one of these technologies. However, SATA drives are more common, cost less and still offer excellent performance for common applications.
Any SSD is better than a hard drive: Even the worst SSD is at least three times as fast as a hard drive. Depending on the workload, the performance delta between good and mediocre SSDs can be subtle.

How much can you spend?

Most consumer drives range from 120GB to 2TB. While 120GB drives are the cheapest, they aren't roomy enough to hold a lot of software and are slower than their higher-capacity counterparts. It only costs an extra £30 to £40 to step up from 120 to 250GB size and that's money well spent. The delta between 250GB and 500GB drives can be £50 to £100, but 500GB is the sweet spot between price, performance and capacity for most users.

There are also some drives (primarily from Samsung) with capacities above 2TB. But they’re typically expensive in the extreme (well over £1,000), so they’re really only worthwhile for professional users who need space and speed and aren’t averse to paying for it.

What kind of SSD does your computer support?

Solid-state drives these days come in several different form factors and operate across several possible hardware and software connections. What kind of drive you need depends on what device you have (or are intending on buying). If you own a very recent gaming desktop or are building with a recent mid-to-high-end motherboard, your system may be able to incorporate most (or all) modern drive types.

Alternatively, modern slim laptops and convertibles are increasingly shifting solely to the gum-stick-shaped M.2 form factor, with no space for a traditional 2.5-inch laptop-style drive. And in some cases, laptop makers are soldering the storage directly to the board, so you can’t upgrade at all. So you’ll definitely want to consult your device manual or check Crucial's Advisor Tool to sort out what your options are before buying.

Which form factor do you need?

SSDs come in four main form factors:



2.5-inch Serial ATA (SATA): The most common type, these drives mimic the shape of traditional laptop hard drives and connect over the same SATA cables and interface that any moderately experienced upgrader should be familiar with. If your laptop or desktop has a 2.5-inch hard drive bay and a spare SATA connector, these drives should be drop-in-compatible (though you may need a bay adapter if installing in a desktop with only larger 3.5-inch hard drive bays free).

SSD Add-in Card (AIC): These drives have the potential to be much faster, as they operate over the PCI Express bus, rather than SATA, which was designed well over a decade ago to handle spinning hard drives. AIC drives plug into the slots on a motherboard that are more commonly used for graphics cards or RAID controllers. Of course, that means they’re only an option for desktops, and you’ll need an empty PCIe x4 or x16 slot to house them.

If your desktop is compact and you already have a graphics card installed, you may be out of luck. But if you do have room in your modern desktop and a spare slot, these drives can be among the fastest available (take the Intel Optane 900p, for example), due in large part to their extra surface area, allowing for better cooling. Moving data at extreme speeds generates a fair bit of heat.

M.2 SSDs: About the shape of a stick of RAM but much smaller, M.2 drives have become the standard for slim laptops, but you'll also find them on many desktop motherboards. Some boards even have two or more M.2 slots so you can run the drives in RAID.

While most M.2 drives are 22mm wide and 80mm long, there are some that are shorter or longer. You can tell by the four or five-digit number in their names, with the first two digits representing width and the others showing length. The most common size is labelled M.2 Type-2280. Though laptops will only work with one size, many desktop motherboards have anchor points for longer and shorter drives.

The largest M.2 drives are 1 to 2TB. So, if you have a generous budget and need a ton of storage space, you should consider other form factors.

U.2 SSDs: At first glance, these 2.5-inch components look just like traditional SATA hard drives. However, they use a different connector and send data via the speedy PCIe interface. U.2 drives tend to be more expensive and higher-capacity than regular M.2 drives. Servers that have lots of open drive bays can benefit from this form factor.


Do you want a drive with a SATA or PCIe interface? 

Strap in, because this bit is more complicated than it should be. As noted earlier, 2.5-inch SSDs run on the Serial ATA interface, which was designed for hard drives (and launched way back in 2000), while add-in-card drives work over the faster PCI Express bus, which has more bandwidth for things like graphics cards.

M.2 drives can work either over SATA or PCI Express, depending on the drive. And the fastest M.2 drives (including Samsung’s SSD 970 drives and Intel’s 760p) also support NVMe, a protocol that was designed specifically for fast modern storage. The tricky bit (OK, another tricky bit) is that an M.2 drive could be SATA-based, PCIe-based without NVMe support, or PCIe-based with NVMe support.

Both M.2 drives and the corresponding M.2 connectors on motherboards look identical, regardless of what they support. So be sure to double-check the manual for your motherboard, laptop, or convertible, as well as what a given drive supports, before buying a drive.

If your daily tasks consist of web browsing, office applications, or even gaming, most NVMe SSDs aren’t going to be noticeably faster than less expensive SATA models. If your daily tasks consist of heavier work, like file transfers, videos or photo editing, transcoding, or ompression/decompression, then you might consider stepping up to an NVMe SSD. These SSDs provide up to five times more bandwidth than SATA models, which boosts performance in heavier productivity applications.

What capacity do you need?

 128GB Class: Stay away. These low-capacity drives tend to have slower performance, because of their minimal number of memory modules. Also, after you put Windows and a couple of games on it, you'll be running out of space. Plus, you can step up to the next level for as little as £30 more.
250GB Class: These drives are much cheaper than their larger siblings, but they are still quite cramped, particularly if you use your drive to house your operating system, a bunch of PC games, and possibly a large media library. If there’s wiggle room in your budget, stepping up one capacity tier to a 500GB-class drive is advisable.
500GB Class: Drives at this capacity level occupy a sweet spot between price and roominess
1TB Class: Unless you have massive media or game libraries, a 1TB drive should give you enough space for your operating system and primary programs, with plenty of room for future media collections and software.
2TB Class: If you work with large media files, or just have a large game library that you want to be able to access on the quick, a 2TB drive could be worth the high premium you pay for it.
4TB Class: You have to really need this much space on an SSD to splurge on one of these. A 4TB SSD will be quite expensive -- well over £1,000 -- and you won’t have many options. As of this writing, Samsung was the only company offering consumer-focused 4TB models, in both the SSD 850 EVO, and the newer SSD 860 EVO models.

If you’re a desktop user, or you have a gaming laptop with multiple drives, you’re much better off opting for a pair of smaller SSDs, which will generally save you hundreds of dollars while still offering up roughly the same storage space and speed. Until pricing drops and we see more competition, these drives will be relegated to professionals and enthusiasts with very deep pockets.

What about power consumption?

If you’re a desktop user after the best possible performance, then you probably don't care how much juice you're using. But for laptop and convertible tablet owners, drive efficiency is more important than speed—especially if you want all-day battery life.

Choosing an extremely efficient drive like Samsung’s 850 EVO over a faster-but-power-hungry NVMe drive (like, say, the Samsung 960 EVO) can gain you 90 minutes or more of extra unplugged run time. And higher-capacity models can draw more power than less-spacious drives, simply because there are more NAND packages in bigger drives to write your data to.

While the above advice is true in a general sense, some drives can buck trends, and technology is always advancing and changing the landscape. If battery life is key to your drive-buying considerations, be sure to consult the battery testing we do on every SSD we test, as well as our Best Storage for Notebook Battery Life feature, which compares the battery performance of over 100 drives.

What controller should your SSD have?

Think of the controller as the processor of your drive. It routes your reads and writes, and performs other key drive performance and maintenance tasks. It’s interesting to dive deep into specific controller types and specs. But for most people, it’s enough to know that, much like PCs, more cores are better for higher-performing, higher-capacity drives.

While the controller obviously plays a big role in performance, unless you like to get into the minute details of how specific drives compare against each other, it’s better to check out our reviews to see how a drive performs overall, rather than focusing too much on the controller.

Which type of storage memory (NAND flash) do you need?

When shopping for an SSD for general computing use in a desktop or laptop, you don't expressly need to pay attention to the type of storage that’s inside the drive. In fact, with most options on the market these days, you don’t have much a choice, anyway. But if you’re curious about what’s in those flash packages inside your drive, we’ll walk you through various types below. Some of them are far less common than they used to be.

Single-Level Cell (SLC) flash memory came first and was the primary form of flash storage for several years. Because (as its name implies) it only stores a single bit of data per cell, it’s extremely fast and lasts a long time. But, as storage tech goes these days, it’s not very dense in terms of how much data it can store, which makes it very expensive. At this point, beyond extremely pricey enterprise drives and use as small amounts of fast cache, SLC has been replaced by newer, denser types of flash storage tech.
Multi-Layer Cell (MLC) came after SLC and for years was the storage type of choice for its ability to store more data at a lower price, despite being slower. To get around the speed issue, many of these drives have a small amount of faster SLC cache that acts as a write buffer. Today, apart from a few high-end consumer drives, MLC has been replaced by the next step in NAND storage tech, TLC.
Triple-Level Cell (TLC) flash is the de facto standard storage type for today’s consumer SSDs. While TLC is slower still than MLC, as its name implies, it’s even more data-dense, allowing for spacious, affordable drives. Most TLC drives (except some of the least-expensive models) also employ some sort of caching tech, because TLC on its own without a buffer often is not significantly faster than a hard drive.

For mainstream users running consumer apps and operating systems, this isn’t a problem because the drive isn’t typically written to in a sustained enough way to saturate the faster cache. But professional and pro-sumer users who often work with massive files may want to spend more for an MLC-based drive to avoid slowdowns when moving around massive amounts of data.
Quad-Level Cell (QLC) tech is being readied as the next stage of the solid-state storage revolution, and as the name implies it should lead to less-expensive and more-spacious drives thanks to an increase in density. But as of this writing, QLC drives have yet to make an appearance in the consumer SSD space.

What about endurance?

These are two other areas where, for the most part, buyers looking for a drive for general-purpose computing don’t need to dive too deep, unless they want to. All flash memory has a limited life span, meaning after any given storage cell is written to a certain number of times, it will stop holding data. And drive makers often list a drive’s rated endurance in total terabytes written (TBW), or drive writes per day (DWPD).


But today’s flash tends to last longer than earlier drives in general. And most drives feature “over provisioning,” which portions off part of the drive’s capacity as a kind of backup. As the years pass and cells start to die, the drive will move your data off the worn-out cells to these fresh new ones, thereby greatly extending the usable lifespan of the drive. Generally, unless you’re putting your SSD into a server or some other scenario where it’s getting written to nearly constantly (24/7), all of today’s drives are rated with enough endurance to function for at least 3-5 years, if not more.

If you plan on using your drive for much longer than that, or you know that you’ll be writing to the drive far more than the average computer user, you may want to invest in a drive with higher-than-average endurance ratings, and/or a longer warranty. Samsung’s Pro drives, for instance, typically have high endurance ratings and long warranties. But again, the vast majority of computer users should not have to worry about a drive’s endurance.

Do you need a drive with 3D flash? And what about layers?

 Here again is a question that you don’t have to worry about unless you're curious. The flash in SSDs used to be arranged in a single layer (planar). But starting with Samsung’s 850 Pro in 2012, drive makers began stacking storage cells on top of each other in layers. Samsung calls its implementation of this tech “V-NAND” (vertical NAND), Toshiba calls it “BiCS FLASH” and most other companies just call it what it is: 3D NAND. As time progresses, drive makers are stacking more and more layers on top of each other, leading to denser, more spacious, and less-expensive drives.

At this point, the vast majority of current-generation consumer SSDs are made using some type of 3D storage. The latest drives often use 64-layer NAND. But apart from looking at small letters on a spec sheet or box, the only reason you’re likely to notice that your drive has 3D NAND is when you see the price. Newer 3D-based drives tend to cost significantly less than their predecessors a the same capacity, because they’re cheaper to make and require fewer flash packages inside the drive for the same amount of storage.

What about 3D XPoint/Optane?

3D XPoint, (pronounced “cross point”), created in a partnership between Intel and Micron (maker of Crucial-branded SSDs), is an emerging new storage technology that has the potential to be much faster than any existing traditional flash-based SSD (think performance similar to DRAM) , while also increasing endurance for longer-lasting storage.


While Micron is heavily involved in the development of 3D Xpoint, and intends to eventually bring it to market, as of this writing, Intel is the only company currently selling the technology to consumers, under its Optane brand. Optane Memory is designed to be used as a caching drive in tandem with a hard drive or a slower SATA-based SSD, while the Optane 900p (an add-in card) / 905P are standalone drives and the Intel 800p can be used as either a caching drive or a standalone drive (though cramped capacities make it more ideal for the former).

Optane drives have much potential, both on the ultra-fast performance front and as a caching option for those who want the speed of an SSD for frequently-used programs but the capacity of a spinning hard drive for media and game storage. But it’s still very much a nascent technology, with limited laptop support, low capacities and high prices. At the moment, 3D XPoint is far more interesting for what it could be in the near future than for what it offers to consumers today. However, if you have a lot of money to spend, the Intel Optane 905P is the fastest SSD around.

Bottom Line

Now that you understand all the important details that separate SSDs and SSD types, your choices should be clear. Remember that high-end drives, while technically faster, won’t often feel speedier than less-spendy options in common tasks.

So unless you’re chasing extreme speed for professional or enthusiast reasons, it’s often best to choose an affordable mainstream drive that has the capacity you need at a price you can afford. Stepping up to any modern SSD over an old-school spinning hard drive is a huge difference that you’ll instantly notice. But as with most PC hardware, there are diminishing returns for mainstream users as you climb up the product stack.