Storage is considered an important factor while buying or upgrading your PCs and laptops. The storage capacity of PCs and laptops gives an idea of how much data a device can store for a long time. The storage drives are used to store, access, and manage all the files on a device. They also play an important role in data transmission, handling large chunks of data.
With the advancement in technologies, the need for a reliable storage drive resulted in the development of various devices.
Hard disk drives (HDDs) were introduced which were easily integrated with the computer circuit. Their limitations were overlooked since these drives were the sole storage drives for any system. Solid-state drives (SSDs) were introduced as a more efficient alternative to HDDs. Their advantage over HDDs has made them popular over the years. Various types of SSDs were developed that offer different data-handling performances. In this article, we will try to explain SSD, their types, and their key differences.
What Are SSDs?
As discussed earlier, solid-state drives ((SSDs) are one of the types of storage drives. They are considered a better upgrade over hard disk drives (HDDs). These storage drives have a different architecture than HDDs. The traditional HDDs use a spinning disk which allows the reading and writing of data. On the other hand, the SSD uses flash memory to store, manage, and even read the data.
Unlike the moving parts of HDDs, an SSD has no spinning disk. Due to this difference, the data moves faster without latency. SSD is mostly installed as an internal storage drive and yet supports external installation. Over the course of years, SSD went through continuous advancements which lead to the introduction of various types. The most popular types of SSDs are the M.2 SSDs and the SATA SSDs, which are explained further.
What Are M.2 SSDs?
Previously known as Next Generation Form Factor (NGFF) SSDs, M.2 SSDs are compact versions of regular SSDs. They are designed specifically for small-size devices where the space factor is given importance. Even with a small size, these storage drives do not compromise their performance. They offer ample storage space, which can be extended up to 2 TB capacity.
The most important advantage of this SSD is that it does not require a SATA interface to connect to a motherboard. Having its own M.2 slot, it offers a very fast data transmission compared to the other types. One important factor behind this faster data transmission is the use of a PCIe interface to connect the motherboard. The M.2 SSDs are further divided into two subtypes, each with its own performance.
Different Types of M.2 SSD
Now that we have learned about the M.2 SSDs, it becomes important to discuss their subtypes. Each subtype differs from the other ones in the terms of interface, performance, and other factors. We will go through these subtypes one by one to understand their important aspects.
1. SATA
The SATA M.2 SSD, as the name suggests, uses the standard SATA III interface. This interface is similar to the regular SATA SSDs Cables which are known for good performance. What makes it different is its smaller dimensions which allow easy installation of the SSD in small devices. Even being an entry-level SSD, it still outperforms HDDs due to the absence of mechanical parts. Hence, a data transmission rate between 400 to 600 MB/s makes it a reliable option over HDDs.
Another selling point of this storage drive is its lower price tag. Since it also uses the SATA interface, it becomes a good alternative to regular-size SATA SSDs. Being a subtype of M.2 SSD, this storage drive does not need multiple cables to connect the motherboard and PSUs. This further helps in accommodating the SATA M.2 SSD in small devices like laptops or ultra-thin notebooks.
2. AHCI
The AHCI ( Advanced Host Controller Interface Protocol) is a type of data transfer protocol. It is a commonly used protocol for SATA HDDs and SDDs. It enables various support functions for storage devices. This protocol was a replacement for the older IDE protocol and allows better data transmission. However, due to its limitation, it was replaced with a better NVMe protocol.
3. NVMe
The NVMe M.2 SSDs were developed by incorporating the newer NVMe data transfer protocol. This ensures an improved data transmission speed over the SATA M.2 SSD. By further pairing it with the PCIe bus standard, this SSD delivers excellent speed and performance. Being a subtype of M.2 SSD, it also uses the PCIe sockets to communicate directly with the CPU.
The NVMe M.2 SSD has been designed for a data transmission speed of 2.5 GB/s. Due to the efficiency of the PCIe bus, this speed drastically increases up to 4 GB/s. Some NVMe SSDs even offer data transmission speed beyond this limit. The speed is totally dependent on the availability of the PCIe lanes.
M.2 SSD Size
Dimension is an important parameter while selecting an M.2 SSD for your devices. Usually, the width of this SSD is fixed to the 22 mm limit. It is however offered in different lengths. The dimension of M.2 SSD can be determined by reading the 4 to 5 digits mentioned on this drive. The first two digits of these numbers indicate the width of the SSD while the remaining digits give you an idea about the length. A size table is mentioned below to understand these different sizes further.
| Identification Number | Description |
| 2230 | 22 mm width and 30 mm long |
| 2242 | 22 mm width and 42 mm long |
| 2260 | 22 mm width and 60 mm long |
| 2280 | 22 mm width and 80 mm long |
| 22110 | 22 mm width and 110 mm long |
Connectors
The M.2 SSD mainly uses three different types of connectors to establish a connection with the motherboard. The major difference between these three connectors is the placement of the key notch and the gap between the edge connector. The B-type connector has its notch placed at a distance of six pins from the left side. The M-type notch has its notch placed at five pins distance from the right side. A combined connector called the B and M connector features a unique design. It has two different notches placed at a distance of six pins from the left and five pins from the right side. It is important to check the motherboard specification before selecting the connector type.
What Are SATA SSDs?
SATA is a short form for the Serial Advanced Technology Attachment interface. As the name suggests, this SSD also supports the SATA interface and its versions. By using the AHCI data transfer protocol, this SSD transits data to the motherboard. The first-generation interface has a data transmission speed of only 150 MB/s. This speed doubled to 300 MB/s with the introduction of SATA interface 2. By the 3rd SATA interface came, the speed had been upgraded to 600 MB/s. The current SATA SSDs run on the sub-versions of the SATA interface 3.
These SSDs are usually larger than the M.2 SSDs in size. The common size of SATA SSD is 2.5-inch which can be further increased. SATA drives were a replacement for the dated PATA drives due to a faster data transfer speed. Once replaced, SATA became the most popular SSD for desktops and laptops. Due to the compatibility of the SATA interface with HDDs and SSDs, it easily adapted to the changing technology.
Working of SATA SSD
In a simple view, SATA SSD transfers data to the motherboard. But, this process is not that simple considering the complex architecture of computer memory. SATA SSD’s working depends on three different factors: the cache, the memory, and the data drive. The cache is the base of all the important calculations. As soon as data is sent to the SATA SSD, the cache receives it. Here, all the calculation and management of data is done with the help of NAND flash memory cells.
The memory acts as a temporary storage of this data. This is where the random access memory (RAM) plays an important role. The data is sent for permanent storage when all the calculations are over. The data drive acts as an ending node of all the operations where the data is stored to retrieve later. Apart from this, SATA SSDs also collect and discard the waste files to ensure optimized performance.
Why Are SATA Drives Used?
Even with the presence of advanced M.2 SSDs, the SATA SSDs enjoy huge popularity. The points mentioned below will give you a clear idea of why SATA drives are used:
- Compatibility: Any drive must offer a certain level of backward compatibility to easily establish a connection. Due to the SATA interface, these drives are compatible with new as well as older motherboards.
- Dimension: Even though the large size of the SATA drive is not desirable for compact devices, it does not matter for desktops. The M.2 drives are not compatible with older computers due to the size difference. The SATA drives perfectly fit the older generation of motherboards.
- Cost: The cost of SATA SSDs are comparatively lower than the M.2 SSDs. This makes it suitable for budget-oriented users. The upgrade cost is also low, which helps in saving money.
- Availability: It is important for a drive to be available for the users. It also includes the availability of all the capacities, all sizes, and all configurations of the drive. This helps the users in selecting the right option which suits their usage.
Difference Between M.2 SSD And SATA SSD
To select between M.2 and SATA drives, we must be aware of certain factors related to both of them. By understanding the key difference between these factors, you can narrow down your search for the correct SSD.
1. Speed
In the case of a storage drive, everything comes down to the overall data handling speed. These drives not only store data but also allows retrieval of this data on demand. Hence, it is expected that quicker data transmission is provided by SSDs. For SATA SSDs, the data transmission speed is limited to 600 MB/s. The M.2 SSDs get the upper hand thanks to an average data transmission speed of 3 GB/s.
2. Type of Interface
The interface plays a crucial role in the data transfer process. It provides a stable connection between the storage drives and the motherboard. For a SATA drive, the standard SATA 3 interface and its sub-versions are used. SATA drives also use the AHCI data transfer protocol to enhance the data transfer process. On the other hand, the M.2 drives use the M.2 interface which is known for its efficiency. It offers an incredible data transfer speed along with wider compatibility. The M.2 interface can be paired with the SATA interface by using an extension. It also supports the NVMe and AHCI protocols.
3. Form Factor
The form factor is considered an important factor when it comes to the physical attributes of an SSD. The shape and size of an SSD matter when installation space is given equal importance. The SATA drives are known for their 2.5-inch form factors. Hence, they are used with computers where no space restrictions are imposed. The M.2 drives are compact in size measuring 22 mm wide with different lengths. They are suitable for portable devices like laptops or notebooks.
4. Installation
Both the M.2 and SATA drives are installed in a unique way due to the difference in their architecture. Hence, the slots on a motherboard are designed according to the SSD type. The SATA SSDs required two cables, one for the motherboard and the other for PSU. The cable connected to the motherboard handles all the data transfer processes. The cable connected to the PSU provides power to the SSD. For M.2 SSDs, direct installation on the motherboard is possible as they do not require different cables. In short, the M.2 SSD is simply screwed on the motherboard.
5. Cost
Along with the specifications, the overall price of an SSD is also considered a crucial factor. The price of the SSD differs from brand to brand, but its average cost is considered here. The M.2 SSDs are usually priced higher than the SATA units due to their performance. For the SATA drives, the prices are comparatively lower than M.2 units. The storage capacity also governs the pricing of these SSDs. SATA drives with higher storage capacity can still cost less than M.2 drives.
Conclusion
SSDs have become popular since they were first introduced to the market. They have been efficiently replacing HDDs thanks to their durability. Even with limitations like higher price tags, they are preferred due to their improved performance and efficient power consumption. With the continuous advancement in SSDs, their subtypes have further enhanced their core qualities. With this article, we aim towards providing you with ample knowledge about SSDs and their subtypes. This information lets you buy or upgrade your SSD according to your needs.
