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Guide to SDXC Memory Cards

What you need to know about SDXC memory cards

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Guide to SDXC Memory Cards

Image courtesy Lexar.

A new breed of memory card has emerged on the scene: SDXC. These flash memory cards can be used in an increasing number of digital camcorders and digital cameras. Here's what you need to know about them.

SDXC vs. SDHC vs. SD Card

SDXC cards are essentially a higher capacity version of the SDHC card (which itself is a higher capacity version of the original SD card). SDXC cards start at capacities of 64GB and can grow to a maximum theoretical capacity of 2TB. By contrast, SDHC cards can only store up to 32GB of data and the venerable SD card can only handle up to 2GB. To learn more about SDHC cards, click here.

For camcorder owners, SDXC cards hold out the promise of storing many more hours of high definition video footage than what you can store on an SDHC card, so there's a clear benefit.

SDXC Card Speed

In addition to offering higher capacities, SDXC cards are also capable of faster data transfer speeds, with a maximum speed of 300MBps. In contrast, SDHC cards can achieve up to 10MBps. To help you find the right speed, SD/SDHC/SDXC cards are broken down into four classes: Class 2, Class 4, Class 6 and Class 10. Class 2 cards offer a minimum sustained data rate of 2 megabytes per second (MBps), Class 4 of 4MBps and Class 6 of 6MBps and Class 10 of 10MBps. Depending on which manufacturer is selling the card, the speed class will either be prominently displayed or buried in the specs. Either way, you should keep an eye out for it.

For standard definition camcorders, an SD/SDHC card with a Class 2 speed is all you would need. It’s fast enough to handle the highest quality standard definition video you can record. For high definition camcorders, cards with a Class 4 or 6 speed rating are fast enough to handle the data transfer rates of even the highest end high definition camcorders. While you may be tempted to spring for a Class 10 card, you'll be paying for performance you don't need in a digital camcorder.

In many cases, SDXC cards will be offered in faster speeds than you need for a digital camcorder. These faster speeds offered by SDXC cards are useful for digital cameras - it enables them to have ultra-fast burst modes - but they're not necessary for digital camcorders.

SDXC Card Cost

SDXC cards began to filter onto the market in late 2010 and early 2011. As with any new memory format offering high capacities and faster speeds, it's going to cost you more than lower capacity, slower SDHC cards. However, as more flash memory card makers offer SDXC cards, the costs should drop rather sharply over the next two years.

SDXC Card Compatibility

One question around any new card format is whether it will work in older devices, or whether newer devices will accept older card formats like SDHC and SD. To answer the first question, an SDXC card may work in an older device that doesn't specifically support it, but you won't enjoy the larger capacities or faster speeds. Most cameras and camcorders introduced in 2011 support SDXC. Support is more limited in cameras and camcorders introduced in 2010. If a camera takes an SDXC card it will always work with SDHC and SD cards.

Do You Need an SDXC Card?

If we're talking strictly for a digital camcorder, the answer is no, not yet. The capacity benefits can be enjoyed by buying multiple SDHC cards and as mentioned above, the speed improvements aren't relevant. However, if you own a high-end digital camera, the speed gains make the SDXC card worth a look.

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