What is the difference between SD and SDHC/SDXC cards?

The SD card, SDHC card, and SDXC card differ in the specifications. The SD card supports a maximum of 2GB, the SDHC supports a maximum of 32GB, and the SDXC supports a maximum capacity of 2TB (2048GB). The digital device supporting the SDXC card is compatible with the SD card and SDHC card. If the device only supports SDHC cards, this device cannot use SDXC cards, but is compatible with SD cards. If the device only supports SD card, it is not compatible with SDXC, SDHC card.

SD is an earlier version and is said to have evolved from MMC. Supports up to 2GB SD Memory Cards are small storage media jointly developed by Panasonic, Toshiba, and SanDisk in 1999. At the same time as SD memory cards were introduced, Secure Digital Card Association (SDA) was established at the same time. Formulate relevant regulations and be responsible for the promotion of SD memory cards. After years of development, the SD card has become the world's highest memory card format for electronic products. It is suitable for mobile phones, digital still cameras (DSCs), MP3 music players, personal computers and other electronic products.

SDHC is a large-capacity SD card, that is, SD High Capacity, which supports SDHC, Secure Digital High Capacity, and large-capacity SD at a maximum size of 32GB. That is, an SD of more than 2G is called SDHC because the early SD used a FAT16 file. The system does not support large capacity, and SDHC is upgraded to FAT32 to support large capacity of 2G or more.

SDXC (SD eXtended Capacity) is a new standard released in 2009 last year. It supports the largest 2TB capacity SDXC is an abbreviation for SD eXtended Capacity. It is the newly proposed standard. In addition to the capacity can be upgraded to a maximum of 2T, it can mainly support 300M. The transmission speed of /s, which is to say "High Speed ​​SD" card. However, there are not many digital cameras supporting SDXC cards. Most of them are new products introduced this year, and SDXC is not backward compatible. It does not support ordinary SD and SDHC card slots and card readers.

For most digital cameras and SLRs, the speed of high-speed SDHC memory cards is sufficient for high-speed continuous shooting and high-definition video capture.