The SD Association has just announced the latest specifications for the widely used Secure Digital (SD) memory card format. The new Ultra Capacity (UC) designation will mean capacities of up to 128 terabytes and the “Express” designation will mean transfer speeds of up to 985 megabytes per second.



SDUC follows in the footsteps of the original SD card, the SDHC (“High Capacity”), and the SDXC (“eXtended Capacity”), raising the maximum storage capacity level from 2TB with SDXC to 128TB, or a 64x increase.

SD Express adds PCI Express and NVMe interfaces to the legacy SD interface, bringing the maximum data transfer rate from 624 MB/s in UHS-III to 985 MB/s, or 1.58 times faster.

And in addition to appearing in SDUC cards, SD Express will also be offered in SDXC and SDHC cards.

Both innovations, part of the SD 7.0 specification, continue the SD Association’s tradition of backward compatibility.

“With SD Express we’re offering an entirely new level of memory card with faster protocols turning cards into a removable SSD,” says SDA president Hiroyuki Sakamoto.

Future SDUC Express cards should be useful for photographers who need to space and speed for working with ultra-high-res still photos and videos.

“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, [and] 360 degree cameras/videos,” the SD Association says.

No word yet on when we’ll be seeing SDUC Express cards hit the market or what storage capacities the initial cards will offer. SanDisk announced a 1 terabyte SDXC card in 2016, but that has yet to materialize on any store shelves, and the current maximum capacity on the market today remains at 512GB.