The SD Association has announced a new SD standard called SD Express. SD Express adds PCI Express and NVMe interfaces to the legacy SD interface. By adding a PCIe interface SD Express cards will be capable of a whopping 985 megabytes per second (MB/s) maximum data transfer rate. To put this speed in perspective, a Sandisk SDHC Extreme Pro UHS-II card has a maximum write speed of 260MB/s and a maximum read speed of 300MB/s. Perhaps the even bigger news is that the maximum storage capacity in SD memory cards will grow from 2TB with SDXC to 128TB with the new SD Ultra Capacity (SDUC) card.
SD Express has been developed to keep pace with the growing performance levels of mobile, computer and imaging devices that are requiring faster and larger capacity media. These new cards are being touted as an entirely new level of memory card with faster protocols that turn cards into a removable SSD. The new SD Ultra Capacity (SDUC) cards are the same physical size as existing SD HC, XC, and UC cards. There will also be SDUC Micro cards available.
SD Express uses the well-known PCIe 3.0 specification and NVMe v1.3 protocols defined by PCI-SIG and NVM Express, respectively, on the second row of pins used by UHS-II cards today. SD Express also has the advantage of being backward compatible with billions of existing SD host products in the market today.
SD Express will deliver speeds necessary to move large amounts of data generated by super-slow motion video, RAW shooting and 8K video capture and playback. SD Express will be initially offered on SDUC, SDXC, and SDHC memory cards.
With ever-increasing resolutions comes higher data rates and with that the need for larger and faster forms of media to store them on. SD Express looks like a good format both speed wise and size wise. We will undoubtedly see these new cards find their way into future cameras that are yet to come to market. There is no current indication of how much these new cards will cost or when they are likely to become available.