Over the last decade, solid-state drives (SSDs) have become the top choice for many compute environments because of their better read/write speeds and lack of moving parts when compared to hard disk drives (HDDs).
However, with many options to choose from, finding the right fit for your needs can be challenging. In this post, we’re going to look at one of the most widely used types of SSD, the M.2, and the most popular (and fastest) protocol available for connecting SSDs to motherboards, non-volatile memory express (NVMe).
While the terms M.2 and NVMe are often used interchangeably, they actually refer to different technologies that can be used together or separately. Simply put: NVMe is a storage and transfer protocol specifically designed for high-performance, non-volatile storage media. M.2 is an SSD form factor that enables high-performance storage. M.2 SSDs connected using the NVMe interface deliver some of the fastest data transfer speeds available.
What is a solid-state drive (SSD)?
SSDs are a type of semiconductor-based storage device that relies on flash memory to store data in a computer. Unlike magnetic storage—such as hard disk drives (HDDs) and floppy drives that store data using magnets—SSDs use NAND technology, a type of non-volatile storage that doesn’t require power to maintain its data. In an SSD, each memory chip is constructed of blocks containing memory cells (also known as pages or sectors) that each have bits of memory. Whereas hard drives have inherent latency and access time because of platters and the movement of read/write heads, SSDs have no moving parts, making them much faster.
What is NVMe?
NVMe (non-volatile memory express) is a protocol for data transfer with reduced system overheads per input/output per second (I/O, or IOPS) that is used in SSDs and flash storage. According to a 2023 International Data Corporation (IDC) report (link resides outside ibm.com), NVMe was designed to speed data transfer to systems connected via a PCI express, a serial expansion bus that’s standard for connecting a computer to one or more peripheral devices. Unlike its predecessor, Serial Advanced Technology Attachment (SATA), NVMe was built for high-performance, non-volatile storage media, making it an excellent choice for both consumer and enterprise workloads. For a full comparison of NVMe and SATA, read “NVMe vs. SATA: What’s the difference?” NVMe can be used at the enterprise level with a smaller infrastructure footprint and using less power than the popular Small Computer System Interface (SCSI).
NVMe SSDs can deliver better response times than HDDs because of improvements to their drivers, allowing for parallelism and polling and helping reduce latency to avoid CPU bottlenecks. In 2011, NVMe storage technology was introduced as an alternative to SATA and Serial Attached SCSI (SAS) protocols, which had been the industry standard for several years. In addition to improvements in storage and technology over its predecessors, NVMe contributed to the development of important technologies that were being developed at the same time, including the Internet of Things (IoT), artificial intelligence (AI) and machine learning (ML).
Peripheral Component Interconnect Express (PCIe) bus
One of the most important differentiators of NVMe SSDs is the way it accesses flash storage. By using a Peripheral Component Interconnect Express (PCIe) bus, it removes the “middleman” controller, greatly reducing latency. However, NVMe’s can also run on any type of “fabric” interconnect—such as Fibre Channel and Ethernet—and within Ethernet, iWarp, RoCEv2, iSER and NVMe-TCP. PCIe Gen4 is the latest PCI Express specification, and its data transfer rate is double Gen3’s. While Gen3 PCIe’s have a transfer rate of 8 giga transfers per second, (GT/s) per PCIe lane, Gen4’s rate is 16 GT/s, or two GB/s per PCIe lane.
Parallel command queues Unlike drives using SCSI protocol, which can only deploy a single command queue, NVMe SSDs can run tens of thousands of parallel command queues at once. With NVMe SSDs, the connection method is independent of the protocol. For example, NVMe PCIe connectors can access a single drive via a PCIe link running the NVMe protocol.
What is an M.2 SSD?
M.2 drives (or Next Generation Form Factor (NGFF) drives) are a kind of SSD that connects to a computer’s motherboard via an M.2 interface. M.2 drives are extremely power efficient compared to other kinds of SSDs and take up less space. Additionally, they don’t require cables of any kind to connect, and they are both smaller and faster than the widely used, 2.5-inch SSDs. Despite their relatively small size, M.2 drives still hold just as much data as their peers (up to 8 terabytes, or TBs) and typically run faster. They’re easy to install and compatible with any motherboard that has an M.2 slot. Even if your motherboard doesn’t have an M.2 port, an M.2 drive can still be connected using an adapter card that fits a PCIe slot.
SATA M.2 SSDs
SATA drives are becoming an increasingly popular form factor due to their compatibility with older technologies. While NVMe SSDs still have more bandwidth, many older computers don’t support either NVMe or PCIe technology, making an M.2 SATA interface the best option. SATA SSDs can achieve a maximum data transfer speed of 6 gigabytes per second (Gbps), which is slower than other, newer interfaces. Strictly in terms of performance, SATA M.2 is the lowest-grade type of SSD on the market. But the technology is still considerably faster than an HDD, with three or even four times the bandwidth. Additionally, SATA M.2 SSDs are more affordable than NVME SSDs, and for motherboards that don’t have room for a 2.5-inch drive, SATA M.2 is a great alternative.
M.2 NVMe SSDs
NVMe technology is characterized by high bandwidth and fast data transfer speeds. Top-performing NVMe drives exceed 3,000 megabytes per second (MB/s), and some of the newer models can reach up to 7,500 MB/s. NVMe M.2 SSDs provide the fastest data transfer speeds on the market, by far. Another attractive feature of NVMe technology is right there in its name: Non-volatile memory. This specification means that power is not required for an NVMe device to retain its data. Unlike other technologies, NVMe M.2 SSDs connect directly to a computer’s CPU using a PCIe socket. This feature enables the drive’s flash memory to function through PCIe as opposed to a SATA driver operating at a considerably slower speed. Through the PCIe bus, an NVMe M.2 SSD drive can achieve a transfer speed of a whopping 20 Gbps, more than three times that of a SATA M.2.
Which kind of SSD is right for you?
Users who are new to these technologies may find themselves asking which is better—NVMe or M.2? The reality is that there really is no comparison. They’re different technologies and you don’t need to choose between them because you can have both. When choosing a storage drive, an NVMe M.2 SSD is one of the fastest and easy-to-install drives available. However, there are many factors to consider besides speed and performance when purchasing a drive. To streamline the process, we’ve compared the most popular technologies using four critical factors: Price, technical specifications, storage capacity and speed.
Price: Until recently, SATA M.2 SSDs were comparably cheaper than NVMe M.2s, making them an attractive option for budget-minded users. However, with the price of NVMe M.2s dropping every year, price isn’t as important a factor as it used to be. As of the writing of this article, a Samsung NVMe and a Samsung SATA M.2 SSD with storage capacities of either one or two TB ranged from between USD 64 and 130 on Amazon.
Technical specs: This is where the difference between the two technologies really begins to stand out. Some older devices simply won’t support NVMe technology, making a SATA M.2 the best choice. Also, before purchasing an NVMe drive, users will want to check the compatibility of their system and make sure it has enough PCIe connections to support multiple devices.
Storage capacity: NVMe and SATA M.2 drives are typically offered in either 1TB or 2TB options. Users looking for something larger can upgrade to 4TB and 8TB models at a considerably higher price point. At the time of writing, 4TB M.2’s of both the NVMe and SATA variety were going for between USD 200 and 300 on Amazon, and their 8TB SSD counterparts were closer to USD 400.
Speed: NVMe M.2 SSDs high-performance, high-throughput and high-speed data transfer capabilities are key differentiators in the market. NVMe…
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