SSD vs. NVMe: What’s the difference?

Recent technological advancements in data storage have prompted businesses and consumers to move away from traditional hard disk drives (HDDs) towards faster, lower-latency solid-state drive (SSD) technology. In this post, we’re going to look at this new technology, as well as the fastest and most popular protocol available to connect it to a computer’s motherboard—non-volatile memory express (NVMe).

While the terms SSD and NVMe are often used to describe two different types of drives, they are actually different data storage technologies that are can used to complement each other. SSDs are a type of semiconductor-based storage used with flash storage, and NVMe is a protocol for data transfer with reduced system overheads per input/output operations per second (I/O, or IOPS) that is used in SSDs with flash memory.

The differences between NVMe and SSD technology are subtle and can be confusing. While every NVMe device is also an SSD drive, not all SSDs are NVMe drives. 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. However, not all SSDs use PCIe technology; some use the older SATA and SAS interfaces that were designed for HDDs, making them compatible with older devices.

What is an SSD?

Before SSDs were invented, HDDs and floppy drives were the most widely used storage drives on the market. But while HDDs and floppy drives both relied on magnets to store data, SSDs use a new technology called NAND—a non-volatile type of storage that doesn’t require power to retain its data. In an SSD, each memory chip is made of blocs that contain cells (also known as pages or sectors) that each have their own bits of memory.

Unlike HDDs that have inherent latency and access time because of their platters, spinning disks and read/write heads, SSDs contain no moving parts, making them much faster. Since the early-to-mid 2000s, SSDs have been rising in popularity in both the consumer and enterprise marketplace due to their superior performance and lightning-fast speeds.

NVMe SSDs

For the fastest data transfer speeds available, look no further than the NVMe SSD. Through its Peripheral Component Interconnect Express (PCIe) bus, NVMe SSDs can achieve transfer speeds of up to 20 gigabytes per second (Gbps)—more than three times the speed of a SATA SSD. Another attractive feature of an NVMe drive is right there in its name—non-volatile memory. This specification means that, unlike other types of drives, power is not required for an NVMe device to retain its memory. Additionally, unlike other technologies, NVMe storage can connect directly to a computer’s CPU using a PCIe socket and enable the drive’s flash memory to function through PCIe as opposed to a SATA driver, which is slower. 

SATA SSDs

Another popular type of SSD is the SATA drive, which has become more popular recently due its compatibility with older technologies. While NVMe SSDs still have more bandwidth, many older computers don’t support either the NVMe or PCIe technology, making a SATA interface the best option. SATA SSDs can achieve a maximum data transfer speed of six gigabytes per second (Gbps), slower than other, newer interfaces, but still considerably faster than a traditional HDD.

Learn more about how NVMe and SATA relate

M.2 SSDs

M.2 drives, introduced in 2012, are a type of SSD that can connect directly into a computer’s motherboard using an M.2 form factor. Compared to other kinds of SSDs, M.2 drives are more power efficient and take up less space. They are also smaller and faster than the widely used 2.5-inch SSDs and don’t require cables of any kind to connect. Despite their relatively small size, M.2s can hold just as much data as their peers—up to eight terabytes (TBs)—and are compatible with any motherboard that has an M.2 slot. When they use the NVMe interface, M.2 NVMe SSDs can deliver some of the fastest data transfer speeds available today.

Learn more about how NVMe and M.2 relate

PCIe SSDs

A PCIe SSD is an expansion card that connects a computer to various components (such as a graphics card or external storage device) using the PCIe serial expansion bus standard. PCIe slots are available in five different sizes (x2, x3, x4 … etc.) with the x referring to the number of lanes each card has for a data transfer.

What is NVMe?

NVMe (non-volatile memory express)is a data transfer protocol that was designed for flash storage and SSDs. It was introduced in 2011 as an alternative to the SATA and Serial Attached SCSI (SAS) protocols that were the industry standard at the time, and it conveys better throughput than its predecessors. In addition to improvements in storage and technology, 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).

Since 2011, NVMe technology has distinguished itself through its high bandwidth and blazing-fast data transfer speeds. Because of improvements to the NVMe drivers that allow for parallelism and polling, NVMe SSDs can optimize response times and write speeds and help reduce latency to avoid CPU bottlenecks. Additionally, NVMe technology has a smaller infrastructure footprint at the enterprise level and uses less power than the popular Small Computer System Interface (SCSI).

Top-performing NVMe drives can surpass 3000 megabytes per second (MB/s), with some of the newer models reaching speeds as high as 7500 MB/s. Unlike its predecessor, Serial Advanced Technology Attachment (SATA), NVMe was designed for high-performance, non-volatile storage media, making it an excellent choice for challenging, data-rich compute environments.

Peripheral Component Interconnect Express (PCIe) bus

NVMe SSDs access flash storage through a PCIe bus that removes the “middleman” controller, greatly reducing latency. However, NVMes 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 PCIes have a transfer rate of eight giga transfers per second (GT/s) per PCIe lane, Gen4’s rate is 16 GT/s, or 2 GB/s per PCIe lane.

Parallel command queues

NVMe SSDs can run tens of thousands of parallel command queues at once, another key differentiator from drives that utilize the older, slower SCSI protocol and can only deploy a single command queue. 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. 

NVMe vs. SSD: What kind of data storage is right for you?

There is no way to accurately compare NVMe and SSD technology, as they are different and often complement each other. NVMe SSDs provide some of the fastest data transfer speeds available, but that doesn’t mean they are necessarily the right choice for your needs. Many factors come into play when choosing a data storage solution. To help with the process, we’ve compared some of the most popular options available by four critical factors: Price, technical specifications, storage capacity and speed.

• Price: Until recently, SATA SSDs were comparably cheaper than NVMe SSDs, making them an attractive choice for budget-minded users. However, the price of NVMe SSDs has been dropping for the past few years as the technology becomes more widely available, making price less and less of a differentiator. Today, the popular Samsung brand of SSDs—in both NVMe and SATA variety and with comparable storage—ranges in price from between USD 64 and 130 on Amazon.
• Technical specifications: Many older devices don’t support the newer, faster NVMe technology, making a SATA SSD the necessary choice. Before purchasing an SSD, users should also make sure their system has enough PCIe connections to support the number of devices they wish to connect. Many motherboards only have two or three slots, which will limit the number of devices they can connect.
• Storage capacity: NVMe and SATA SSDs usually come in either 1TB or 2TB options. Users looking for more capacity can upgrade to the 4TB and 8TB models, but at a higher price point. At the time of writing, 4TB NVMe and SATA SSDs cost between USD 200 and 300 on Amazon, while 8TB SSDs were going for closer to USD 400.
• Speed: NVMe SSDs’ key differentiator is speed and performance. NVMe technology uses a PCIe interface that enables it to connect directly to a CPU, reducing latency and improving responsiveness. But some users simply don’t need that level of speed, in which case a SATA SSD could be a slightly cheaper option. While quite not as fast, SATA SSDs still transfer data much faster than their older HDD counterparts. Depending on your needs, the speeds of a SATA SSD might be sufficient.

SSD and NVMe use cases

At the enterprise level, the speed and performance of NVMe technology are difficult to ignore. While some enterprises still use SATA SSDs, they are more common among consumers looking to upgrade the speed and performance of a laptop or PC they’re using for gaming or to run basic office applications. Here are some of the most common use cases for SSDs.

• High-performance/high-speed computing: NVMe SSDs’ ability to handle parallel processing makes it an ideal solution for many of today’s most demanding and complex compute environments. Many high-demand applications, such as high-frequency financial trading apps and AI and ML deployments, rely on NVMe SSDs for speedy access to large volumes of data.
• Compute-intensive applications: Apps that feature real-time customer interactions often rely on NVMe technology to run their workloads. Examples of these apps include e-commerce, personal finance and many cloud-native applications.
• Data centers: NVMe SSDs help data centers everywhere expand their storage capabilities and achieve lightning-fast transfer speeds. While SATA SSDs are still in use at the enterprise level, according to a recent report from Enterprise Strategy Group (ESG) (link resides outside ibm.com), nearly three-quarters of businesses have either already switched to NVMe SSD storage or are planning to in the next year.
• Video editing: Many video editors use NVMe and SATA SSDs to expand their storage and still get the high processing speeds they need. One example is the slim, small, highly portable NVMe M.2 SSD that is an ideal solution for lightweight computers like laptops, notebooks and ultrabooks.
• Gaming: Serious gamers everywhere depend on the fast load times that both NVMe and SATA SSDs provide. Both kinds of SSDs can deliver a smooth, fast gaming experience at comparable prices, as well as improve the speed and performance of day-to-day applications for any PC build.

IBM and SSD and NVMe solutions

SSDs help consumers and enterprises achieve the fast data transfer speeds they require. For gaming enthusiasts and video editors, older, SATA SSDs are often enough, but for enterprise workloads, the NVMe SSD is fast becoming the industry standard. IBM Storage FlashSystem 5200 provides compact, powerful storage along with all the benefits of NVMe technology. The 5200 helps enterprises achieve greater speed, performance and scalability with their data storage solution.

Explore IBM Storage FlashSystem 5200

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