What is SDHC™?

SDHC™ stands for Secure Digital High Capacity, and it is a new standard developed by the SD Card Association to support capacities beyond the 2- gigabyte* (GB) limit of the original "standard" SD Cards. Standard SD Cards use a file format called FAT16 that supports capacities up to 2GB, while the new SDHC cards use a file format called FAT32 that has a maximum capacity of 32GB. The first SDHC Cards introduced to the market in 2006 typically have capacities of 4GB, although higher capacity cards will be offered in the future.

SDHC cards also feature minimum speed class ratings. A Class 2 card has a minimum sustained write speed of 2MB/s; Class 4: 4MB/s, and Class 6: 6MB/s.

Today's standard SD cards can be read by new cameras or other devices equipped with SDHC card slots (also called SDHC hosts), but the full capacity of SDHC cards cannot be read in standard SD card slots. This means that new cameras or other devices with SDHC slots will generally be able to read existing SD cards, but the new higher capacity SDHC cards are not intended for use in cameras or other equipment with existing SD card slots.

Most PCs equipped with SD card slots are expected to be able to read either the FAT16 or FAT32 file format.

( * When used herein in relation to memory density, gigabyte and/or GB means 1,024x1,024x1,024 = 1,073,741,824 bytes.
Usable capacity may be less. For details, please refer to specifications ).