The SD Association has announced a new memory card technology that adds the popular PCI Express and NVMe interfaces to the legacy SD interface.


Images showing the formats and labelling of the new SDUC and SD Express cards. (Source: SD Association.)

The PCIe interface in the new SD Express memory cards will enable them to offer a maximum data transfer rate of 985 megabytes per second (MB/s), while the NVMe upper layer protocol provides an advanced memory access mechanism.  These innovations maintain the SDA’s commitment to backward compatibility and are part of the new SD 7.0 specification. New cards featuring these technologies will open the way for new possibilities for content creation and data storage.

According to the SD Association, SD Express delivers speeds necessary to move large amounts of data generated by data-intense wireless 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.  The maximum storage capacity for SD cards will also be expanded from 2TB with SDXC to 128 TB with the new SD Ultra Capacity (SDUC) card.

Even though they have similar data transfer speeds the new SD cards will be incompatible with SATA solid state drives because of hardware differences. SSDs have  integrated controllers to handle file management and need to communicate with a system. SD cards require a host controller on any device with a card slot. SD Express will initially be offered on SDUC, SDXC and SDHC memory cards. Users with high storage requirements are most likely to choose the SDUC cards when capacity takes priority over speed.

A new video ( explains more about SD Express. Additional information is available in the following white paper,  and by visiting the Association’s website at