SD Association Announces the Latest Evolution in SD Memory Cards – Including New Speed Classes

Industry News

by Alexandra ThompsonOctober 24^th, 2023

The SD Association (SDA) is a non-profit organization established in 2000 and composed of around 800 tech companies (including Apple, Canon, Microsoft, and Google) that develop and promote the strict industry standards for SD cards. Full-size SD and microSD cards comprise more than 80% of the memory card market, and now the SDA says that the newest iteration is the biggest evolution since their introduction. The SD 9.1 Specification defines a new speed class and multi-stream access for SD Express Cards, so let’s see what it’s all about!

microSD Express card is twice as fast

Speed class defines a card’s minimum write speed. This distinction is especially important when recording video, which requires a constant minimum write speed during recording. Now, the SD Association has updated its specs with new PCIe standards, allowing microSD Express to reach speeds up to 2 GB/s. According to the SDA, “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.”

The speed class of a card will also be more clearly indicated so consumers will know what they’re buying.

New speed classes

Several speed classes were created by SDA for real-time speed recording: Speed Class, UHS Speed Class, and Video Speed Class. The current Video Speed Class ensures minimum recording speeds for a single data stream. In contrast, says the SDA, “The SD Express Speed class defines a few minimum assured performance levels using the PCIe/NVMe interface, including multi-stream recording.”

SD Express Speed Class is necessary for tasks like recording high-resolution and non-compressed videos in real time or handling multiple streams on a one-card interface.

“By defining minimum assured sequential performance standards for SD Express memory cards, the SDA helps both device manufacturers and consumers ensure the best recording and playback of all types of content.”

Hiroyuki Sakamoto, SDA president

SD Association spec 9.1 – features in a nutshell

The newly established SD Express Speed Classes include 150, 300, 450, and 600. For instance, SD Express Speed Class 600 assures a minimum recording speed of 600MB/s when both the card and host device employ the PCIe bus and adhere to the access rules outlined in the specification. It also enables up to eight simultaneous streams to be recorded. Multiple data streams can be recorded as long as their combined recording speed stays within the supported speed class. Furthermore, consistent performance is ensured even when mixing write and read operations.

In addition, new features address power management, thermal management, and access rules for multi-stream recording.

What do you think of the new SD Express speed classes? Is there anything else you think the SDA should be addressing? Let us know in the comments below!