An SD Card category that uses the PCI Express (PCIe) and NVMe interfaces. Introduced in 2018, SDHD, SDXC and SDUC cards are available as SD Express cards, which are backward compatible with the SD Card readers in use.
Over the PCIe bus, an SD Express card plugged into an SD Express host can reach up to 985 MB/sec, a 50% increase over the UHS-III bus in full-duplex mode. See
SD card classes,
SD card,
PCI Express and
NVMe.
microSD Express
Full-size SD Express cards did not take the world by storm, but the microSD format is used in many devices. See
microSD.
SD Express Minimum R/W
Speed Class Performance
150 150 Mbytes/sec
300 300 Mbytes/sec
450 450 Mbytes/sec
600 600 Mbytes/sec