The SD Association today revealed first details of SDXC (Secure Digital Extended Capacity), its sequel to the current SDHC standard for flash cards. The format uses the exFAT file system to dramatically increase the maximum storage space from the arbitrary 32GB of SDHC to a full 2TB and would be enough to hold roughly 4,000 RAW photos or 60 hours of HD footage. Notably, the format also no longer sacrifies speed in the process, according to the organization. Unlike SDHC and other card formats, the fastest speeds should be possible even at the 2TB limit.
SDXC itself should be significantly faster than SDHC and fast enough to handle continuous, high-speed RAW shooting or HD video capture. While very early speeds haven't been revealed, the SDA anticipates cards that can read and write at 104MB per second during 2009 and for the standard to top out at 300MB per second.
The format is externally identical to SD and SDHC and should provided incidental performance gains to SDHC, SD and SDIO when put into a supporting reader. No mention is made of when the first cards or supporting devices will appear other than at some point later this year, though the specification should be published within the first three months.