microSD EXPRESS DOUBLES SPEEDS, NEW SD EXPRESS SPEED CLASSESINTRODUCEDNew Specifications defines new speed class with multi stream access for SD
Express Memory Cards
SAN RAMON, CALIF— October 19, 2023 — SD Association (SDA) today announced
the latest evolution of SD Express memory cards doubling microSD Express memory
card speed up to 2GB/s as defined in the microSD Addendum v8.0, plus four new SD
Express Speed Classes to ensure guaranteed minimum sequential performance levels,in the new SD 9.1 specification including support of Multi-stream access and related
Power and Thermal Management assuring the guaranteed performance. The SD 9.1
specification helps consumers identify the right card for their device while giving
manufacturers new tools to assure minimum level of performance of SD Express
memory cards and have means to guide consumers what type of cards will assure
specific application operations.
The latest generation of microSD Express uses the PCIe interface delivering a 1,969
megabytes per second (MB/s), nearly 2 gigabytes per second (GB/s) speeds by using
the PCIe Gen4 x1 lane as defined in the latest update to the microSD Addendum
version 8 specification. microSD Express was introduced with 985 MB/s speed
maximum data transfer rate and the NVMe upper layer protocol in the SD 7.1
specification. The increase in speed gives product designers more storage options andSSD level performance for a variety of size constrained devices requiring easily
repairable or upgradeable storage.
SD Express Speed
Classes

SD Express Speed
Class Pictographs

Minimum Read/WritePerformance

SD Express Speed Class 150

150 Mbytes/Sec

SD Express Speed Class 300

300 Mbytes/Sec

SD Express Speed Class 450

450 Mbytes/Sec

SD Express Speed Class 600

600 Mbytes/SecThe SD Express Speed Classes are used exclusively on SDXC, SDUC, microSDXC
and microSDUC memory cards offering the SD Express bus. Changes in memory
technology necessitate the need to define speeds as NAND flash technology continues
to evolve. SD Express is the most significant evolution for SD since it was introduced in2000. It meets new and evolving market needs to support increased performancerequirements of controllers, memories, and other application interfaces. SD Express canfully support almost every use case demanding higher speed removable or semi- more -removable memory cards and is ideal for meeting the growing number of Right toRepair laws.
“By defining minimum assured sequential performance standards for SD Express
memory cards, the SDA helps both device manufacturers and consumers ensure thebest recording and playback of all types of content,” said Hiroyuki Sakamoto, SDA
president. “We doubled the speed of microSD Express to 2GB/s to give productmanufacturers more storage options capable of handling the most demanding storage
uses making SD Express memory cards a compelling, ecologically sound choice
making it easier to repair and upgrade devices.”
New Features
In order to optimize the SD Express speed class usage under various power levels andthermal conditions - Leveraging NVMe specifications, SD Express memory card now
offer several Power Management settings through Maximum Power (MP) values. The
card consumes power up to one of the MP values set by the host device to manage
card temperatures. SD Express memory cards use a new Thermal Management feature
where the card indicates a group of its specific thermal thresholds. The host device maythen set appropriate Thermal Management parameters for the card according to thetarget class and the selected PCIe bus mode, much like an MP value for powermanagement.
The SD 9.1 specification defines the access rules required to ensure the minimum
defined performance of the PCI/NVMe interface in SD Express cards, including multistream access of up to eight streams.
The SDA has prepared a whitepaper providing more details about the new features andSD Express Speed Classes defined by SD 9.1.
SD Express
A growing list of devices and memory cards support SD Express. SD Express offers
SSD performance levels with transfer speeds up to ~4GB/sec thanks to the PCIExpress® (PCIe®) and NVMe Express™ (NVMe™) architectures. The first SD Express
cards were introduced with SD7.0 specifications for the full-size SD form factor
supporting PCIe Gen 3 x1 interface with speeds of 985 MB/s. SD8.0 defines three
additional PCIe interfaces – PCIe Gen 4 x1, PCIe G3 x2 and PCIe Gen4 x2 quadrupling
speeds to 4GB/s. SD7.1 specification added SD Express 985 MB/s to the microSD form
factor and the microSD Addendum version 8 specification doubled speeds to 2 GB/s byusing PCIe Gen 4 x1. SD Express gigabyte transfer speeds bring new storage
opportunities for devices with demanding performance levels capable of moving large
amounts of data generated by data-intense wireless or wired communication, superslow 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 andautomotive to name a few.
SD Association

The SD Association is a global ecosystem of nearly 800 technology companies charged
with setting interoperable SD standards. The Association encourages the developmentof consumer electronic, wireless communication, digital imaging and networking
products that utilize market-leading SD technology. The SD standard is the number one
choice for consumers and has earned more than 80 percent of the memory card market
with its reliable interoperability and its easy-to-use format. Today, smartphones, tablets,drones, IoT devices, HDTVs, audio players, automotive systems, computers, digital
cameras and digital video cameras feature SD interoperability. For more information
about SDA or to join, please visit the Association’s website, https://www.sdcard.org.
SD logos are trademarks licensed by SD-3C LLC.
PCIe® - PCI Express, is a standard developed by PCI-SIG® and PCIe® is a trademark
owned by PCI-SIG.
NVMe™ - NVM ExpressTM, is a standard developed by NVM Express Inc. and NVMe™
is a trademark owned by NVM Express Inc.
###Media Contact
Kevin Schader
SD Association
1.925.275.6670
media@sdcard.org