SSD vs. HDD: What s the Difference. What is an ssd card

Triple Level Cell (TLC): Each of these cells can store three bits of data per cell and comes in large sizes at a decent price. The compromise is slower read and write speeds and less precision, as well as reduced service life due to increased energy consumption.

SSD vs. HDD: What’s the Difference?

Do you like cheap and plentiful storage or fast and shockproof? Here’s how to choose between a traditional hard drive and an SSD in your next computer.

If you’ve purchased an ultraportable laptop at any point in the past few years, you’ve most likely received a solid state drive (SSD) as your primary boot drive. Larger gaming laptops have also transitioned to SSD boot drives, while only some budget machines continue to favor hard drives (HDDs). Meanwhile, the boot disks in prefabricated desktops are now mostly SSDs, with the exception of the cheapest models. In some cases, a desktop computer comes with both, with an SSD as boot drive and a hard drive in addition to larger capacity storage.

However, if you only have to choose one, how do you choose? Let’s take a look at the differences between SSDs and HDDs and discuss the pros and cons of each to help you make up your mind.

HDD and SSD Explained

A traditional spinning hard drive is the primary non-volatile storage in a computer. This means that information about it does not “disappear” when the system is turned off, unlike data stored in RAM. A hard drive is basically a metal plate with a magnetic coating on which your data is stored, whether it’s last century weather reports, a high-resolution copy of the original Star Wars trilogy, or your digital music collection. The read / write head on the arm accesses the data as the platters rotate.

An SSD performs the same basic function as a hard drive, but instead, data is stored on interconnected flash memory chips that retain data even when no power is flowing through them. These flash chips (often referred to as “NAND”) are of a different type to those used in USB sticks and are usually faster and more reliable. SSD drives are therefore more expensive than USB flash drives of the same capacity. (See our detailed guide to SSD jargon.)

However, like flash drives, SSDs are often much smaller than hard drives and therefore offer manufacturers more flexibility in the design of a computer. While they can replace traditional 2.5-inch or 3.5-inch hard drive bays, they can also be installed in a PCI Express expansion slot and even mounted directly to the motherboard, a common configuration on high-end laptops today and all-in-one . (These onboard SSDs use a form factor known as M.2. View our types of the best M.2 SSDs and get much more information on these diverse types of SSDs.)

Note: In this story, we’re going to be talking primarily about internal drives, but pretty much everything is about external drives as well. External drives are available in both large desktops and compact portable computers, and SSDs are gradually becoming an increasingly large part of the external drive market.

Another question is whether your computer can use the SSD. It all depends on the age of the computer and the way it was designed. Now let’s look at this question.

What is a solid-state drive?

SSDs work differently than traditional hard disk drives (HDDs) because they have no moving parts. While hard drives use rotating platters of disks to access information, SSDs store data on flash memory chips, much like a smartphone, USB drive, or flat tablet. Since the disk does not have to wait for the platter to turn to where the data is located, all memory chips are available at the same time. This makes it much easier for users to access their information at high speed.

For this reason, SSDs are built differently and come in a variety of shapes and sizes, but are more expensive to manufacture. Even as prices are falling, the cost of hard drives with similar capacity is more than double in 2020. This is especially true of the fastest and largest SSDs. Prices can also go up significantly once you break over the 1TB mark.

SSD advantages

External SSD drives are also becoming more and more popular.

Solid-state drives are becoming more common in everything from high-end gaming PCs to entry-level laptops, and for good reason. They have several advantages over traditional hard drives and built-in flash memory (eMMC).

No Moving Parts: The big problem with moving parts in hard drives is that they are a major point of failure. If any of the moving parts break, the entire drive becomes unusable. This makes traditional hard drives susceptible to damage and wear over time.

SSDs have their own lifetime limitations, but are generally more durable and reliable. There are no moving parts to damage and no drive motor to break. This reliability makes SSDs ideal for portable external drives that may undergo more stringent usage and handling.

Speed: SSDs can write or read data at an incredible speed compared to hard drives and even eMMC, which is useful for transferring large blocks of data. More importantly, their random access times are given in microseconds, not milliseconds. That’s why SSD systems start up so fast, games load so fast, and SSD based systems are just fast and responsive.

Mobility: SSDs are smaller and lighter than previous drives. This development enables the creation of today’s ultra-thin laptops, tablets and other mobile devices. The thinnest SSDs are just millimeters wide and only a few inches long, making them ideal for the smallest high-speed devices.

Low failure rate: After years of development, SSDs run much less frequently than hard drives and maintain their speed throughout their service life. Low failure rates are due to extensive material and feature improvements such as Error Correction Code (ECC) that keep SSDs on the right path.

Size and Design: SSDs can come in many different shapes and sizes depending on the number of chips you have and the overall chip layout. They can fit into the graphics card slot, 2.5-inch drive bays and M.2 slots. There are SSDs for just about every occasion, which makes them much more versatile than other types of storage.

Longer Lifespan: Each SSD has a lifetime that is limited by the drive’s ability to properly store the electric charges sent to it. The lifespan of hard drives is typically measured by the number of terabytes that can be written to the drive before the flash cells degrade. That could mean a decade or more of use for the typical buyer. Studies have shown that SSDs not only last longer than their HDD counterparts, but also last longer than experts expected.

However, if you only have to choose one, how do you choose? Let’s take a look at the differences between SSDs and HDDs and discuss the pros and cons of each to help you make up your mind.

Why use a solid-state drive?

New SSD drive ready for use in XPS 13

There are many reasons why you should choose an SSD over a standard hard drive.

Laptops can withstand bumps when traveling with you – having a storage device that is unaffected by shock is a huge boon. Hard drives with their moving parts can be damaged if they spin when being dropped or impacted. SSDs are much less prone to impact.

Mobility is a huge part of laptops; SSDs are smaller and lighter than HDDs. This saves space for putting other equipment in the laptop and reduces weight and thickness. SSDs also require less power, so your laptop’s battery should last longer.

Most people who have been using Windows for years know how long boot times can be when using a hard drive. The differences in how quickly applications load on your computer can be minimal – you probably won’t notice if your Office applications load in two seconds instead of four – but using an SSD to boot Windows 10 will significantly reduce the time you spend spinning your thumbs.

In addition to all these benefits, SSDs also have a much lower failure rate than HDDs. If you are backing up important data, saving it to an SSD is never a bad idea.

Choosing the right type of memory

There are three types of memory to look out for when purchasing an SSD:

Single Level Cell (SLC): Each of these cells can contain one data bit, either 1 or 0. Therefore, only two possible values ​​can be read from each cell.

For this reason, SLC memory is the fastest and most accurate when it comes to writing, consumes the least power, and will last the longest.

The trade-off is that it’s also the most expensive. SLC solid state drives are typically used in enterprise scenarios because of their price, but are affordable for everyone.

Multilevel Cell (MLC): Each of these cells can store two bits of data per cell – 1 and 0. Since a cell can store both bits, there are four possible values: 00, 11, 01, and 10.

MLC memory can therefore have a larger amount of memory without increasing the physical size, is available at a lower cost, but has slower and less precise write speeds. They also consume more power and wear out about 10 times faster than SLC memory due to increased power consumption.

Remember, we are not talking about longevity in months or years – we are talking about decades. By the time most SSDs are worn out, they will likely be long obsolete due to whatever storage technology comes next. MLC solid state drives are the standard drives found in most high-end devices today.

Triple Level Cell (TLC): Each of these cells can store three bits of data per cell and comes in large sizes at a decent price. The compromise is slower read and write speeds and less precision, as well as reduced service life due to increased energy consumption.

The best place for most people is probably an MLC solid state drive with a SATA III connection in a desktop computer, while most people will enjoy the same in their laptop, albeit with an M.2 connection.

Add-In Card SSDs (AIC)

Overall, AIC SSDs are expected to be much faster than most other drives as they run on the PCIe express bus and not SATA. As mentioned above, PCIe is the faster type of SSD and therefore will have higher performance than SATA, so AICs can be much faster. In addition, AIC disks are preferred over M.2 disks as they can access more lanes on the PCIe. They can only be used on desktops, so their drive plugs into the motherboard and are most commonly used with RAID controllers or graphics cards.

Hard drive

Hard drives, a traditional mass storage device that runs inside a computer. They cost significantly less due to their lower performance, but have a high battery discharge rate. In addition, they are usually used as a more practical memory card for storing files and multimedia such as photos or videos.

HDDs, despite their low speeds, can store much more data than SSDs. SSD drives have a capacity of 64 GB to 4 TB, while hard drives can store 250 GB to 14 TB of data.

Which SSD Should You Use?

The type of SSD to use depends on the device. For computers, check your motherboard to find out what sockets you have. Different devices will support different types of drives.

If you’re a gamer and want to optimize your PC for gaming, you’ll likely get a PCIe SSD because of its faster interface. Your games will launch and run faster if installed on an SSD than on a traditional hard drive. Gamers need a computer drive that can access data very quickly. Also, if you’ve ever played games, you know that games contain large amounts of data such as audio, high-definition graphics, and more, sometimes even exceeding 100 GB of data.

SSD disks

Just downloading a game is not all the data the game stores. When you play your game, data is also stored. Every time your player progresses through the game, data is stored. Every time your player interacts with another player, the data is stored. Every time your player starts another mission, the data is stored. Data is saved for everything.

If it takes two to three minutes to load a game from your hard drive, think about how much faster it will take to load it to the SSD. The longer it takes to load the game, the more disrupted the gameplay will be.

For daily performance that does not require high-speed, high-intensity data transfer, you can get a SATA SSD.

There are still traditional hard drives that can be used for data storage. It just won’t transfer that fast and will likely take more battery life. Note that smaller capacity drives have fewer memory modules and will in turn have lower performance. Hard drives are typically for those who want to keep a lot of old photos and videos that they won’t have to check.

Whether your data is corrupted or not transferred depends on the readability of the drive. Typically SSDs are more reliable because they do not require any moving parts to function, while hard drives have to write data to the disk with the risk of data corruption.

Solid state drive prices have dropped drastically over the years, so you can upgrade without a hitch, you just need to make sure your device is compatible with the drive.

SSDs are becoming available in larger capacities. The greater the capacity, the more economical they are. A simple calculation can help you decide exactly how much SSD storage you will need on your computer.

There are various types of SSDs on the market today. You’ve probably heard the terms “SATA”, “NVMe”, “PCIe”, and “M.2”, but what exactly are they?

First, the different types of SSDs mainly depend on the connection interface between the memory unit and the computer or server. Let’s dive into each type.

Various types of SSDs

Different types of SSDs (image source: Tech Society)

The first interface or generation used with SSDs is called Serial Advanced Technology Attachment (SATA). It is the most used interface among hard drives and mass storage devices.

SATA provides speeds of up to 600 MB / s, and its size fits most notebooks and PCs, hence its popularity. SATA is also available in a smaller size, referred to as mini-SATA (mSATA).

SATA is the slowest of all SSD types, but still transfers data up to 5 times faster than hard drives.

Non-Volatile Memory Express (NVMe) is a protocol for SSDs that enables data exchange at speeds up to 2600 MB / s – almost 5 times faster than SATA SSDs. NVMe SSDs are newer than SATA SSDs and typically use a PCIe connection to peripherals, discussed in more detail later.

NVMe SSDs are more expensive than SATA SSDs and usually require more power. Therefore, they are only used for specific needs, for example for companies that prioritize high processing and transfer speeds.

The NVMe protocol also works with flash memory, which means that even external or portable NVMe SSDs will perform just as fast as internally connected NVMe SSDs.

PCIe Connector

You can also categorize SSDs according to the connectors used which define the data transfer speed.

PCIe is the same connector that is used to connect high-performance graphics cards directly to the motherboard. When NVMe SSDs use PCIe slots, they provide the fastest data processing and transfer rates possible.

However, the difference in speed or bandwidth is most noticeable with larger files (50 GB or more), but when booting Windows or launching a game, it is not much different from using typical SSDs.

M.2 Connector

Formerly known as Next Generation Form Factor (NGFF), the M.2 connector ensures that the SSD achieves the fastest possible speed (up from 2600MB / s). If your computer motherboard does not have an M.2 connector, alternatively a PCIe card with an M.2 connector is used to connect the NVMe SSD to the motherboard.

If your computer’s motherboard already has an M.2 connector, you’ll find mass storage labeled “SATA M.2” or “NVMe M.2”. However, if the motherboard does not have one and has a PCIe card with a built-in M.2 slot, it will be labeled “PCIe NVMe M.2 SSD.”

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The M.2 connector is relatively small and is intended to replace the mSATA. It is also suitable for small notebooks as well as larger devices. The M.2 connector is compatible with SATA, PCIe and even USB 3.0.

Advantages and Disadvantages of SSDs

From what we’ve covered so far about SSDs, you now have a pretty good idea of ​​their main benefits.

Let’s summarize: they’re much faster than traditional drives. They are also more reliable in the sense that they provide more stable performance. Moreover, they are energy efficient and smaller.

What about the disadvantages of SSD drives? Well, SSDs are lagging behind on a few issues:

  • Price Point: Price is the most important disadvantage of an SSD. While they’ve gotten cheaper and become more affordable every day, they’re still more expensive than hard drives. That said, SSDs are still not suitable for everyone, especially for users on a budget.
  • Storage capacity: some users prefer storage capacity over performance as they use it to store usually large files such as movies, music, photos, etc. While there are SSDs that can provide up to 4TB of storage, they are still limited in capacity if you compare them with hard drives.
  • Limited Write / Erase: SSDs have a limited write / erase cycle. For example, consumer grade SSDs have a limited number of write / erase cycles, ranging from 3,000 to 5,000 cycles. Premium SSD drives can have write / erase cycles of up to 100,000 cycles.

To demonstrate the difference in speed, we upgraded a 6-year-old gaming PC to replace its hard drive with a SATA SSD and ran a series of tests. The results are amazing:

What are solid-state drives used for?

The adoption of SSDs began in the high-performance technology areas and in enthusiast PCs, where extremely fast access times and high disk bandwidth justify the higher cost. But they have since become an accepted option – and even the default choice – in cheaper laptops and desktops.

SSDs have specific advantages in the following areas:

Business: Businesses working with massive amounts of data (such as development environments or data analytics) often rely on SSDs as access time and file transfer speed are critical.

Games: Gaming computers have always pushed the limits of current computing technology, justifying relatively expensive hardware in favor of gaming performance. This is especially true of storage as modern hit games constantly load and save files (e.g textures, maps, levels, characters).

Mobility: SSDs have a low energy requirement, which contributes to better battery life in laptops and tablets. SSDs are also shock resistant, reducing the risk of data loss if mobile devices are dropped.

Servers: Enterprise servers need SSDs for fast read and write to properly support client computers.

For a more complete picture of why you should attach an SSD to a hard drive, check out this article.

What are the different types of SSDs

When you buy an SSD, you will come across many different terms such as mSATA or PCIe. So what does it all mean? Here’s an introduction to what you need to know.

To connect an SSD to the system, you need to connect it via a specific interface. Common interfaces are:

PCIe and NVMe SSDs: PCI Express (PCIe) is typically used to connect graphics cards, network cards, or other high-performance peripherals. This interface offers high bandwidth and low latency, making it ideal when you need lightning-fast communication between SSD and CPU / RAM. SSDs using this type of connection are based on the Nonvolatile Memory Express (NVMe) standard, which offers higher input performance per second (IOPS) and even lower latency than SATA (more on that in a moment). NVMe offers raw bandwidth of up to 16 GB per second which, thanks to multiple parallel channels, runs at speeds of up to 4000 MB per second.

NVME SSD connected via PCIe interface

mSATA III, SATA III and traditional SSDs: Serial Advanced Technology Attachment (SATA) is an older interface specifically designed to store data at speeds up to 6 GBit / s or around 600 MB per second. SATA is slowly being phased out by NVME which is much faster. However, older desktops or laptops with a hard drive will still benefit from the upgrade to a SATA based SSD.


SSDs come in all types of capacity, starting at around 32GB and reaching up to 5TB in the consumer space. (Of course, capacity is much higher for enterprise-class storage at proportionally higher prices.)

In the short-lived netbook era (remember? They were cheap, but slow and crappy), the famous Asus Eee PC series used 1-4GB of SSDs as storage from which parts of the operating system were run for faster access. This was the first widespread use of SSD drives. Since then, ultrabooks and eventually desktops have started adopting SSDs. Popular sizes today range from 250 GB to 500 GB, which is enough space to store the Windows operating system, the most popular programs, and many personal files.

In this guide, we will help you understand what an SSD is, what is the difference between an SSD and a hard disk, the different types of SSDs, and how to choose the best one.

How to Clone a Hard Drive to an SSD

It is unlikely that a new SSD, or even a new hard drive, will come preloaded with the operating system your computer needs. Cloning an existing hard drive solves this. However, this may not be possible all the time. For example, you may have installed an SSD in a computer that previously had a damaged hard disk. If so, you can do a so-called clean install and start over. Each operating system manufacturer has different instructions. Here is a link to Microsoft’s clean install procedure and Apple’s Mac clean install instructions.

As we said at the beginning, SSDs cost more per gigabyte than hard drives. You may not be able to afford an SSD as large as your current drive, so make sure your data will fit on the new drive. If this does not happen, you may have to shrink first. Also, give yourself some space to move around. The last thing you want to do is immediately maximize your new high-speed drive.

You cloned the drive and transferred the SSD to the computer. What are you doing with the old disk? If it still works properly, consider reusing your purchased external disk enclosure for migration. Store it as an external drive by itself or in a disk array such as a NAS device. You can use it for a local backup – something we strongly recommend besides using a cloud backup like Backblaze. Or just use it as extra space, for example for photos or music. Check out the blog posts for step-by-step guidance for Windows and Mac.

Make Sure to Back Up!

SSD upgrades are common, but that doesn’t mean nothing is going wrong that can put you to a standstill. If your PC is working fine before updating your SSD, make sure you have a full PC backup that you can restore your data from in case something goes wrong.

More Questions About SSDs?

You can read other posts from our SSD 101 series.

About Andy Klein

Andy Klein is a major exponent of the Backblaze storage cloud. He has over 25 years of technology marketing experience and has shared his knowledge of cloud storage and computer security at events, symposia and panels at RSA, SNIA SDC, MIT, Federal Trade Commission and hundreds of others. He currently writes and rumors about disk stats, Storage Pods, cloud storage, and more.

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