Secure Digital, or SD, cards come in a variety of sizes, capacities, and speeds. These cards are intended to be used with a wide range of devices including tablets, phones, cameras, and more. The standard has been around for a while and is ideal for flash with its current exFAT file system. This file system allows for larger files than FAT32 but lacks NTFS journaling. SD cards also have security with a write-protect notch, but other features are optional.
The SDXC designation applies to SD cards between 32Gb and 2TB in capacity. The UHS, or Ultra High Speed, rating has further implications for performance. For example, UHS-II cards must be capable of 156 MBps full-duplex or 312 MBps half-duplex. UHS-II cards have 17 pins but are backward compatible. They pull between 720mW and 2.88W of power and the bus speed is nominally 52 MHz.
Our SDXC cards are UHS-II and further rated for V90. This means video speed class 90, meeting the requirement for a minimum sequential write speed of 90Mbps which corresponds to a bitrate of about 700Mbps. We offer cards between 64GB and 512GB rated for 280/250MBps read/write. Our cards use the newest 112-layer BiCS5 3D TLC from Kioxia to ensure high performance and reliability.
For more information on speeds and other specifications, please see Wikipedia's page.