What are SDHC Cards

SDHC (Secure Digital High-Capacity) is a new Flash memory card based on the SDA (Secure Digital Association) 2.00 specification. SDHC provides removable memory storage for compatible digital devices, including cameras, camcorders, PDAs, MP3 players and more.
The increasing use of high-definition video and high-resolution digital photography demands higher storage capacity and more demanding data transfer rates. Because of this, the new SDHC cards guarantee a minimum sustained data transfer speed, not a maximum speed. There are three available speeds — Class 2, Class 4 and Class 6.

SDHC cards are classified to guarantee a specific sustained DTS. This potentially saves consumers money, as flash cards are priced not only according to capacity, but also to speed. For example, if a product's maximum DTS is 2MB/sec, dishing out extra cash for Class 4 or Class 6 SDHC cards would be a waste of money. Conversely, devices that can utilize the 4MB/sec or 6MB/sec DTR will perform significantly better with Class 4 or Class 6 SDHC cards, respectively.Secure Digital was forced to create a new specification for SDHC cards when the previous specification topped out at a capacity of 2GB. This occurred previously when SD cards hit the 512MB wall. The new 2.00 specification should last a bit longer, as it allows SDHC cards to reach a maximum capacity of 32GB. Secure Digital is so-named because of its ability to protect copyright content through digital rights management or DRM. Because of this, it is a favored flash memory format in the audiovisual industry. SDHC cards are about the size of a postage stamp. Insiders expect them to be available through several different manufacturers by summer 2006, and prices will vary. Before purchasing, be sure your device is compatible. There are several card formats available on the market, and devices are proprietary. If a device manual does not list SDHC cards, or state it is "SD specification 2.00 compatible," the device cannot utilize these cards.

SD vs SDHC

The look and feel of a SDHC card is exactly the same as an ordinary SD but the difference is in size (capacity). SDHC cards usually hold more than 2 Gigabytes of Data. They are also faster than the "traditional" SD cards. (Note that some next generation SD cards such as class 2, 4 or 6 actually perform much faster than generic traditional SD cards).

Compatibilty is also another factor, not all devices that currently take SD cards as a storage medium are able to accept SDHC cards. You should check with your device manufacturer to see if it supports that format.