What is SDXC?
SDXC? (SD Extended Capacity) is an SD? memory card format that is based on the SDA 3.0 specification. Today, SD and SDHC? cards, which are based on the SDA 2.0 specification, can reach capacities up to 32GB. The SDA 3.0 specification, on the other hand, enables SD cards to "extend" beyond this 32GB capacity limit and reach higher capacities: from 32GB up to 2TB.
SDXC memory cards use the newer "exFAT" file system that is more efficient for SDXC's large capacities, while SD and SDHC memory cards use the FAT32 file system. This difference is the reason that the new SDXC format is NOT backwards compatible with host devices that only take SD (128MB to 2GB) or SDHC (4GB to 32GB) cards.
PLEASE NOTE: Use of SDXC memory cards in non-SDXC compatible host devices may result in data loss, as the non-SDXC hosts do not understand the file system. Contact your device manufacturer for details.
SDXC FAQs | Lexar