The SD Association today announced the SD 7.0 specification which introduces SD Express and SD Ultra Capacity (SDUC). Products utilizing the new SD Express standard can make use of the PCIe interface and the NVMe protocol and should be able to achieve throughputs of up to 985 MB/s. SDUC allows for storage capacities of up to 128 Terabyte.
Currently, the maximum storage capacity for SD cards is 2 TB for SDXC cards. With new SD Ultra Capacity cards this should grow to 128 TB. For now, both numbers are only theoretical limits, the largest capacity SD card that is currently commercially available is a 512GB model from PNY.
The new SD Express standard has been designed to make sure SD cards can keep up with the large throughput demands generated by super-slow motion video, RAW continuous burst mode, 8K video capture and playback, and 360 degree cameras. To keep up, SD Express uses the PCIe 3.0 interface and the NVMe 1.3 protocol. Despite that SD Express memory cards use PCIe and NVMe, they will still work with older devices. When the cards are inserted into older devices,they will use the UHS interface.
The SD Association writes in a white paper (PDF) that SD Express cards might only partially support SD features like the possibility to password lock and write protect memory cards. A feature that for sure won’t be supported with SD Express cards is the SD Content Protection for Recordable Media (CPRM), according to the SD Association. The white paper also mentions that SD Express cards won’t have speed classes.
Despite the announcement of the new specifications, it’s not known when the first SD Express and SDUC products will become available. Now the specification is finished, manufacturers can start to work on products that make use of them.