SD card marking

Bus Interface

SD = 12.5MB/s

SDHC = 25MB/s

UHS-I = 50MB/s

UHS-II = 156MB/s Full Duplex or 312MB/s Half Duplex

UHS-III = 312MB/s Full Duplex or 624MB/s Half Duplex

SD Express PCIe 3.0 x1 = 1GB/s

SD Express PCIe 3.0 x2 = 2GB/s

SD Express PCIe 4.0 x1 = 2GB/s

SD Express PCIe 4.0 x2 = 4GB/s

Speed Class

V90 = 90MB/s minimum write

U3 = 30MB/s minimum write

Class 10 = 10MB/s minimum write

Bus speed reference:

SATA III SSD = 750MB/s

PCIe 3.0 x4 M.2 = 4GB/s

PCIE 4.0 x4 M.2 = 8GB/s