Non-Volatile Memory Express or NVMe is a high-performance and scalable data transfer and storage protocol used in flash memory technology and solid-state drive implementation. It is also called Non-Volatile Memory Host Controller Interface Specification or NVMHCI. This protocol has been integrated into high-end desktop and laptop computers, external storage peripherals, and mid-range and flagship mobile devices such as smartphones and tablet computers. Several manufacturers have also designed hard disk drives using this protocol. This article lists and explains the pros and cons or advantages and disadvantages of NVMe.
Pros of Non-Volatile Memory Express: Main Advantages of NVMe
1. Generally a Faster Flash Storage Protocol
One of the reasons why iPhones and iPads tend to be faster and snappier than most Android smartphones and tablets is that Apple has used NVMe for its flash storage. Most manufacturers use the Universal Flash Storage or UFS standard for mid-range and even some flagship Android devices and Embedded Multimedia Card or eMMC for budget-level devices.
Note that UFS started to become a new standard in 2014 because it has specific advantages over eMMC. To be specific, based on real-world comparisons, UFS 2.0 has a sequential read of 350 MB/s and a sequential write speed of 150 MB/s. This is higher than the read-write speeds of eMMC with a sequential read of 250 MB/s and sequential write speed of 125 MB/s.
Furthermore, unlike eMMC, UFS can read and write at the same time, and is twice energy-efficient when not in operation. This standard soon became widely used in external flash drives and internal solid-state drives of laptops. The first smartphone that used UFS was the Samsung Galaxy S6 which was released in 2015. Other Android manufacturers followed suit.
Non-Volatile Memory Express emerged as the newer and better standard for flash storage because of its advantages over UFS. It first became popular in high-end laptops equipped with solid-state drives. Manufacturers prefer this protocol because it is faster and more efficient. Examples include MacBook devices from Apple and high-end Windows-based laptops.
The release of the iPhone 6S in 2015 showcased the advantage of NVMe over UFS. This device has internal storage based on Triple Level Cell NAND connected via Non-Volatile Memory Express. Speed test results revealed that the iPhone 6S outperformed other flagship smartphones of that time with its read speed of 402 MB/s and write speed of 163 MB/s.
2. Works Efficiently With Solid-State Drives
Earlier generations of solid-state drives used bus protocols such as Serial ATA or SATA, Serial Attached SCSI or SAS, or Fibre Channel to interface with a computer system. The mass availability of these storage devices resulted in the wider utilization and preference for the SATA bus interface because of its advantages over SAS and Fiber Channel.
However, similar to SAS, SATA was designed primarily for hard disk drives or HDDs. Thus, because it is not a native interface and a legacy technology for solid-state drives, it held back the advantages and potential of using storage solutions and devices based on flash memory. This is where the features, capabilities, and advantages of NVMe come into the picture.
Non-Volatile Memory Express used over the PCI Express or PCIe bus protocol was introduced as a solution to utilize and maximize the advantages of solid-state drives. It was designed from the ground up and specifically for NAND solid-state drives based on PCIe. The intention was to introduce a particular interfacing protocol that would efficiently work with SSDs.
Understanding the advantages of Non-Volatile Memory Express requires understanding how it differs from SATA. Hence, as a backgrounder, although the SATA storage protocol serves as a bridge between flash memory and the computer system, there are other application layers in between. These include the flash controller, SATA driver, and software RAID.
NVMe is faster and more efficient because it uses a shorter technology stack. It removes selected application layers to establish a direct link between the flash memory and the computer system. This shorter stack supports data transport efficiency and reduces latency. This characteristic is useful in operating systems that constantly read and produce small bits of data.
3. Flexibility in Implementation and Applications
This protocol also comes in different form factors. Earlier NVMe solid-state drives with “half-height, half-length” and “full height, and full length” add-in card form factors while U.2 and U.3 were introduced as a response to newer iterations to PCIe and evolving hardware requirements. The M.2 SSD is another newer form factor that uses the M.2 form factor standard.
Note that the M.2 form factor specifically emerged as a more modern type of internally mounded expansion card. Furthermore, depending on the motherboard and user preference, this form factor is compatible with either the standard SATA interface or the faster PCIe interface. An M.2 device used for SSD takes less space and looks cleaner than other form factors.
It is also worth mentioning that the Non-Volatile Memory Express protocol supports different hardware environments to include internal desktop and laptop storage and external storage solutions. It also supports various operating systems such as Windows from Microsoft, macOS from Apple, Linux distributions such as Ubuntu, and ChromeOS from Google.
Remember that Apple has demonstrated the use of this protocol in mobile devices and a mobile operating system beginning with the introduction of the iPhone 6S. Of course, because it was impossible to fit a standard SSD in a smartphone, what the company did was to introduce some modifications to the NVMe protocol and develop its own custom PCIe controller.
Cons of Non-Volatile Memory Express: Key Disadvantages of NVMe
1. Considerably Expensive than Other Protocols
Take note that hard disk drives are cheaper than solid-state drives because they are based on older and established technologies with more efficient manufacturing processes. This has helped in driving down their manufacturing costs. Lower production costs translate to lower end-user prices. The existing demand also helps bring down the end-user price further.
A solid-state drive has higher manufacturing costs and higher end-use price points. The same is true for other related storage technologies based on flash memory. But the cost and price has started to go down. This comes from the maturing technology and expanding market demand due to the popularity of portable devices such as laptops, smartphones, and tablet computers.
However, when comparing different data transfer and storage protocols, a notable drawback or disadvantage of NVMe is that it is more expensive than SATA, eMMC, and UFS protocols. This is the reason why flash memory storages or solid-state storages based on Non-Volatile Memory Express are often found in mid-level to top-tier consumer electronic devices.
The protocol also depends on more expensive high-performance solid-state drives. It is also not cost-effective in situations that require storing large volumes of memory. Non-Volatile Memory Express is still a newer technology than the other three protocols and there is a smaller but expanding demand for storage based on this protocol because it is relatively new.
2. Legacy and Other Compatibility Issues
Utilizing flash or solid-state storage devices based on PCIe and NVMe on older desktop and laptop computers, as well as data servers and other machines, might be not feasible or practical due to the cost implications. Several older devices use motherboards with more established data transfer and storage interfaces such as SATA and form factor standards such as U.2.
What this means is that there is a need to replace these older motherboards to accommodate high-performing storage. Another option is to replace these machines as part of a storage system upgrade. Doing either of these two has obvious cost implications. The second option can be impractical for systems or machines that are still working and remain serviceable.
Availability is also an issue despite the inherent flexibility, possible applications, and notable features or advantages of NVMe. Newer machines used in servers and data centers that are based on this protocol are compatible with the M.2 form factor. This fact limits the selection of storage solutions compared to other storage protocols and form factor standards.
It is also worth mentioning that implementing flash storage based on Non-Volatile Memory Express in smaller devices such as smartphones and tablets is not readily doable. Remember that Apple has to design a modified PCIe controller to fit the entire technology within a small real estate. This came with additional manufacturing costs and processes.
3. Overheating Issues and Shorter Lifespan
Another disadvantage of NVMe is its higher susceptibility to heating issues. A particular SSD based on this protocol tends to generate more heat than a counterpart SSD based on SATA. This comes from the fact that it has a higher performance and its small form factor results in less efficient heat dissipation. Heating is more observable during extreme workloads.
Nevertheless, to mitigate the heating issues and avoid overheating, there are several strategies that can be taken into consideration. The most apparent is the use of a suitable heat management or cooling system. It is also important to mount a particular NVMe solid-state drive in a place or area far from other heat-producing hardware devices or with adequate airflow.
Another drawback of Non-Volatile Memory Express is that NVMe SSDs tend to have shorter lifespans than SATA SSDs. The reason for this stems back to the complex architecture of the entire hardware device and more specific hardware components. The higher performance also hastens the natural wear and tear that is unavoidable in all hardware.
It is still important to underscore the fact that the lifespan of these storage devices is still enough in most use cases. The issue is negligible to the average retail user. However, for extensive applications, such as in the case of servers and data centers used in cloud computing, this issue would require consistent performance monitoring and regular hardware evaluation.
Rundown: Advantages and Disadvantages of NVMe
Non-Volatile Memory Express is undeniably superior over Embedded Multimedia Card and Universal Flash Storage. This protocol also maximizes the advantages of solid-state drives over hard disk drives. The advantages of NVMe make it ideal in various high-performance use cases such as video gaming, content creation, multitasking, and data-intensive workloads. There are still some notable drawbacks and limitations but the benefits still outweigh the potential and notable performance improvements.
