SD Express gigabyte speeds bring new storage opportunities for devices with demanding performance levels

The consumer market has found the speed classes as useful means for product manufacturers to tell consumers which speed class is required to allow proper operation of their features and at the same time, help consumers identify the right card to use for their device.

The world of digital storage is constantly evolving, with demands for faster and more reliable performance increasing by the day. In response to these growing needs, the SD Association, the organization responsible for setting the standards for SD memory cards, has announced a new SD card specification that promises to revolutionize the way we store and transfer data. In this article, we will explore the exciting new speed classes and performance features introduced by the latest SD card specification, and delve into the potential impact they will have on various industries and everyday consumers.

SD Express

The cards can move large amounts of data generated by data-intense wireless or wired communication, super- slow motion video, RAW continuous burst mode and 8K video capture and playback, 360 degree cameras/videos, speed hungry applications running on cards and mobile computing devices, ever evolving gaming systems, multi-channel IoT devices and automotive to name a few. SD Express will be offered on SDHC, SDXC and SDUC memory cards.

The consumer market has found the speed classes as useful means for product manufacturers to tell consumers which speed class is required to allow proper operation of their features and at the same time, help consumers identify the right card to use for their device. It also allows host manufacturers to optimize their hosts by using the defined access methods to the card. As NAND technology advanced, the access methods have changed and the last speed class spec defined is the known Video Speed Classes used over the SD UHS-I and UHS-II interfaces.

With the introduction of SD Express cards and its PCIe/NVMe interface, there was a need to adapt the existing Video Speed Classes to operate over NVMe.  SD9.1 has introduced new SD Express Speed Classes 150, 300, 450, and 600.

512 sd card
512 GB SD Card

These SD Express Speed Classes were created to meet the requirements of any applicable host device or products that require minimum writing performance using the PCIe/NVMe interface offered by SD Express such as with real-time video recording. The table below describes each SD Express Speed Class and minimum data transfer rate of the corresponding SDXC/SDUC or microSDXC/microSDUC memory cards. The SD Express Speed Class Pictographs indicated will be used on an SD Express memory card, packaging and in a device manual to clearly indicate its Speed Class. Consumers only need to match the host device with the right card to enjoy the best possible experience.

“SD Express’ use of even faster PCIe and NVMe architectures to deliver faster transfer
speeds creates more opportunities for devices to use SD memory cards,” .

said Mats Larsson, Senior Market Analyst at Futuresource

SD Express is a memory card standard that utilizes PCIe and NVMe architectures to achieve faster data transfer rates and improved storage capacity. The SD 9.1 Specification introduces new features and enhancements to the SD Express standard, including power management, thermal management, access rules for multi-stream recording, and new speed classes.

The SD Express Speed Classes defined by the SD Association are E150, E300, E450, and E600, and they ensure minimum sequential performance levels, including multi-stream access. The SD 9.1 Specification also defines access rules for the PCI/NVMe interface in SD Express cards, including multi-stream access of up to eight streams.

These advancements allow for faster data transfer rates, improved storage capacity, and SSD-level performance in size-constrained devices. The SD Express standard is used exclusively on SDXC, SDUC, microSDXC, and microSDUC memory cards offering the SD Express bus.

Implementing an SD Express interface requires a hardware update of the host SD interface. SDA has provided several whitepapers explaining how easy it is to add SD Express to virtually any host device. There’s also a whitepaper providing more details about the new features and SD Express Speed Classes defined by SD 9.1.

sd card
SD Card

Benefits of using sd express memory cards

Ultra-High Performance

SD Express memory cards leverage the PCIe and NVMe interfaces, offering faster data transfer rates, with read and write speeds as high as 4 GB/s, making them suitable for data-intensive applications such as video recording and editing.

Increased Storage Capacity

The SD Express standard allows for capacities of up to 128TB, providing ample storage space for large amounts of data, making it suitable for a wide range of devices and consumer electronics.

SSD-Level Performance

SD Express cards offer SSD-level performance, effectively turning them into removable SSDs, which is particularly beneficial for applications requiring high-speed and responsive storage solutions.

SD Express

Compatibility and Versatility

SD Express cards are backward compatible with existing SD slot architectures, ensuring compatibility with a wide range of devices. Additionally, the introduction of microSD Express extends the possibilities for high-speed applications, offering a versatile storage solution.

Ease of Maintenance and Serviceability

SD Express cards can be used to replace SSDs as an embedded or semi-embedded memory card, providing benefits in situations such as automotive applications with high wear leveling. This allows for increased serviceability and replaceability, offering a compelling array of options for product manufacturers when designing memory and storage needs.


The SD Express standard reduces costs to businesses by supporting both UHS-I and PCIe/NVMe interfaces, providing highly responsive and cost-effective removable memory card solutions for demanding applications.

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