What changes with MicroSD Express is that the second row of pins from UHS-II cards is repurposed to support PCIe 3.0 x1 connections, with the new standard utilising the NVMe protocol to offer transfer speeds of up to 985MB/s. This change will allow future SD cards to provide transfer speeds that surpass SATA Solid State Drives, which is an amazing feat given the small form factor of MicroSD cards.



In effect, this breaks backwards compatibility with UHS-II and UHS-III devices, though UHS speeds of up to 104MB/s can still be utilised. With MicroSD Express, speeds of up to 985MB/s are possible, which is great news for future high-performance mobile devices.

Alongside their SD 7.1 specification, the SD Association has revealed its MicroSD Express standard, upgrading the humble SD card with PCIe connectivity and NVMe as its upper layer protocol. In short, the performance if NVMe SSDs is coming to the world of MicroSD cards, while also offering backwards compatibility with older standards like SD and SD-UHS104.