What is an SSD Drive | Different types of SSD Drives

What types of SSD exist is one of the questions that some users are asking and what is an SSD drive. In this tutorial I will try to dispel all these doubts, and have a clearer understanding of what an SSD is.

What differences exist with respect to HDDs, or SSHDs, as well as the existing types? Everything you should know to keep in mind when purchasing a new unit for your computer.

What is an SSD Drive?

An SSD (Solid State Disk), or solid state disk, is a variant of the classic HDD (Hard Drive Disk). The HDD is made up of electromechanical parts and magnetic platters where data is stored magnetically.

In an SSD there are no moving parts, only flash memory chips where data is stored electrically. This allows SSDs to have some quite remarkable advantages over HDDs.

See Also: What is SSD Cache and Its Uses

So little by little they are displacing the latter and taking over almost the entire market for internal hard drives of the most modern equipment and even for external devices such as hard drives, USB hard drives, NAS, etc.

The 3D NAND flash memory cells (erasable and writable) of these SSDs can use different technologies, and also come in different formats or with different connection interface. That is why we dedicate this tutorial to see all the most remarkable types that exist.

Advantages of an SSD

The advantages of an SSD compared to an HDD and even an SSHD (SSD+HDD hybrid) are:

• Reliability – With no moving parts and improved reliability of flash memory cells (increased read and write cycles). SSDs now have greater durability than HDDs or SSHDs without a doubt, and even better resistant to shocks.
• Low consumption: Being solid state, based on integrated components, these hard drives have a lower consumption than HDDs. HDDs need more power to move the head through the electric motor and rotate the platters at speeds of thousands of
• Silent: Having no moving parts, they are completely This is advantageous in many cases, especially in equipment intended for sound studios where quieter alternatives are sought, such as fan less equipment, etc.
• Access speed: The speed of writing and reading on an SSD is much higher than that of an HDD. This is especially noticeable in some details, such as starting the computer, loading programs and video And could even affect the FPS of an open world video game, where a large amount of data needs to be accessed.
• Security: while in other units when data is deleted it will remain until it is overwritten, in SSDs this deletion is faster, so it is safer.
• Compact: They are very compact hard drives, usually with less weight and smaller size than an HDD. This is especially good for laptops.
• Lower temperature – The temperature generated by these solid state hard drives is also lower, so it will contribute to the overall performance of the computer and the life of the components.

Disadvantages of an SSD

Of course, SSDs also have some disadvantages compared to HDDs and SSHDs like:

• Price: With equal capacities, the SSD drive is considerably more expensive, since it is a more sophisticated memory.
• Capacity: There are no SSDs with capacities as high as HDDs, so if you are looking for a very high-capacity hard drive, it is best to opt for an HDD. Little by little the SSDs are advancing in this sense, and you can already find some of 1TB, 2TB, etc., compared to capacities of 10TB, 12TB, of the HDD.
• Data recovery: If the SSD breaks it will be impossible to recover the data, something that does not happen with an HDD. In case of HDD the data can be recovered in a laboratory with the appropriate tools and in a clean room. It has even been possible to recover information from a much damaged HDD or after a fire in a building…
• Hybrid RAID Issues – Mixing SSDs and HDDs in a RAID system is not a good idea. Yes, you can have both in other cases without a For example, a main SSD with the operating system and software installed and another secondary HDD with the data.
• Limited Life – Flash cells have a limited write and erase life, so called cycles. While some HDDs can withstand between 1 and 5 million cycles, SSDs average around 100,000 cycles.

What are the Different types of SSD Drives

They can be cataloged according to different characteristics. Therefore, the question about what types of SSD exist is answered in several ways:

1. Types of According to Memory

One of the ways to classify SSDs is by the memory technology they use. The main differences between them are the number of bits they can manage per cell or memory cell. We can find these basic types:

NOR: They use flash cells with NOR gates, they were the oldest units and had a shorter duration.

NAND: They are the most modern, and use this other type of logic gate, allowing greater duration and performance. On the other hand, depending on the type of NAND cell, some sub variants have been developed, such as:

• SLC (Single Level Cell): It is an older type of NAND flash memory, where only one bit of information can be managed in each cell. However, it is faster in access and more durable.
• MLC (Multi Level Cell): As its name suggests, it was also popular in some SSD drives, being able to manage two bits for each memory cell. This increased the storage density per cell, but also reduced the durability of the cells.
• TLC (Triple Level Cell): The performance is somewhat lower, and it does not tolerate too many access cycles either. The positive thing about this NAND flash cell is its higher storage capacity, so it has a good GB/€ ratio.
• QLC (Quad Level Cell): This arises as an evolution of the TLC, with the same advantages and disadvantages, but being able to store four bits instead of three.

2. SSD Types by Form Factor

On the other hand, SSDs can be classified according to the form factor, that is, the physical characteristics and dimensions. For example, we can find:

2.5″: They are designed to be used in laptops or desktop PCs in bays of this size, smaller than the usual 3.5″ in which many HDDs usually come. This format is used by SATA3 drives.

See Also: Uses of Network Attached Storage

M.2: Is the version that has become the current standard, being the most popular. It is a small module that plugs directly into a slot on the motherboard. Within this format we also have:

• mSATA: it is a reduced format, designed for computers where the size is more limited. They use a SATA interface.
• NVMe: They are smaller than the previous ones and with better performance when using a PCI Express interface.

There are also other formats, but they are not as popular as U.2, HHHL, etc.

3. Depending on the interface

Depending on the interface or connection, SSDs can also be classified in this other way:

• USB: Actually SSDs don’t usually have a USB connection, except for some external drive. However, there are enclosures for internal SSDs that transform them into external ones through a SATA/USB or PCIe/USB converter, etc. The speed is limited by the USB connector, being from 480 Mb/s of 2.0 to 5 Gb/s.
• SATA3: These were popular early on, although these types of drives are still being sold today. They use a 2.5″ form factor, and have a transfer speed of 6 Gb/s.
• eSATA: They are a variant of the previous ones for external use. It shares characteristics with SATA, although the speed in this case is 3Gb/s.
• PCI Express: This interface is preferred by most SSDs due to its speeds. It can transfer data at speeds of 15.8 Gb/s per lane of PCIe 4.0, up to 64 Gb/s per lane of future PCIe 6.0, going through 31.6 Gb/s per lane of PCIe 5.0.
• NAS (Network Attached Storage): You can also find NAS drives that use SSDs as main drives instead of HDDs. In this case, the interface is not wired (at least directly), since it is connected to the network to access it remotely.

4. According to Controller

According to the SSD controller we can also find two other variants, one of them already mentioned above:

• AHCI (Advanced Host Controller Interface): They are used in non-PCIe SSDs, such as SATA.
• NVMe (Non-Volatile Memory Express): They are used in the most modern PCIe, with better efficiency, performance and interoperability than the previous ones.

5. Internal or External

Of course, if we look at where the SSDs are going to be installed, we can also differentiate between:

• Internal: for installation inside computers or cases, and for permanent use.
• External: to use as removable drives.

What is your favorite and why? Don’t forget to comment.