SDXC

SDXC stands for Secure Digital eXtended Capacity, a memory card standard developed by the SD Association. Introduced to extend the capacities available beyond SDHC, SDXC cards are designed to meet higher storage needs while sharing the same physical SD card form factor. They are backward compatible in the sense that hosts that support SDXC can read them, though older devices that only support SDSC/SDHC may not recognize SDXC cards.

The official SDXC specification defines storage capacities from 64 gigabytes up to 2 terabytes. To accommodate large files such as high-definition video and extensive image collections, SDXC cards typically use the exFAT file system. Some devices may require exFAT support in their firmware, and in some cases formatting the card to exFAT outside the device may be necessary for proper use.

Performance and interfaces for SDXC cards come from newer bus standards. Many SDXC cards use the Ultra High Speed (UHS) bus interfaces, including UHS-I, UHS-II, and UHS-III, which enable faster transfer rates. In addition, newer revisions include SD Express, which adds PCIe and NVMe signaling to achieve even higher speeds on compatible hosts and cards.

Usage considerations include device compatibility and file system support. Before purchasing, verify that the host device supports SDXC and exFAT. Check the card’s speed class and bus type (for example, UHS-I with Class 10 or U3 ratings) to ensure it matches the intended workload, such as 4K video recording or rapid continuous shooting.