SD 9.1 specs double microSD Express card speeds to 2 GB/s, introduce new speed classes for SD Express

With the latest SD 9.1 specifications, miniSD Express cards may reach speeds of up to 2 GB/s and the SD Express standard is receiving support for multi-stream access up to eight streams plus power and thermal improvements via four new speed classes.

microSD Express cards can now take advantage of the PCIe 4.0 X1 specs, doubling the initial 985 MB/s speeds up to 1,969 MB/s. On the other hand, the SD Express standard that is featured only on SDXC, SDUC, microSDXC and microSDUC memory cards remains capped at 4 GB/s, but it is now grouped into four distinct classes that ensure a minimum read/write speed in MB/s. Thus the new classes are E150, E300, E450 and E600.

As explained by SDA president Hiroyuki Sakamoto, “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.”

The new power and thermal management features allow for increased efficiency. Since not every workload requires the maximum performance (MP) setting, a card can now suggest necessary and sufficient MP values according to the targeted SD Express speed class and the selected PCIe bus mode. Thus, the host device can select an appropriate MP value depending on the card’s capabilities so that the card does not consume excessive power and does not overheat.

Some of the applications that benefit most from the increased microSD Express and SD Express speeds include data-intensive wireless or wired communication, super-slow motion video, RAW continuous burst mode and 8K video capture and playback, 360-degree cameras/videos, multi-channel IoT devices and automotive entertainment systems.

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