SD Express – SD Express is a high-performance evolution of the Secure Digital (SD) memory card standard, introduced by the SD Association in June 2018 with the SD 7.0 specification. It leverages PCIe (Peripheral Component Interconnect Express) and NVMe (Non-Volatile Memory Express) protocols, commonly used in SSDs, to deliver significantly faster data transfer speeds and higher storage capacities compared to traditional SD cards.
SD Express cards are compatible with existing SD slots (SDHC, SDXC, SDUC), but require SD Express-compatible hosts to achieve full speeds. In older slots, they revert to slower speeds (e.g., UHS-I at 104 MB/s or High-Speed at 50 MB/s). Note SD Express uses a second row of pins for PCIe/NVMe, which differs from UHS-II, so it’s not compatible with UHS-II readers without reverting to UHS-I speeds.
Here ia a timeline of the specification’s development, along with links to the corresponding press releases for reference:
SD Express is being integrated into an increasing number of consumer products. Adoption is accelerating across sectors such as next-gen mobile computing, edge AI, high-performance video capture, drones, and gaming. In 2025, Nintendo confirmed that its upcoming Switch 2 will exclusively support microSD Express for expandable storage. As of August 2025, SD 9.2 is expected to further enhance performance, though official details aren’t public yet.
SD Express and UFS
UFS (Universal Flash Storage) and SD Express are advanced storage technologies designed for high-performance applications, but they differ in form factor, use cases, and technical specifications.
- UFS: A high-speed flash storage standard developed by JEDEC, primarily used in smartphones, tablets, and embedded systems. It’s designed for fast, low-power, and reliable data storage with a focus on mobile and embedded applications.
- SD Express: An SD card standard by the SD Association, leveraging PCIe and NVMe protocols to deliver SSD-like performance in a removable, compact form factor. It targets devices like cameras, gaming consoles, and IoT systems.
