by Staff Writer
Many of your personal electronics may use memory cards to store digital photos, music files and other data. Different memory card formats are designed for different devices, and their shape and capacity can vary widely. This memory card buying guide includes basic information to help you find memory cards that have the storage space you need and are compatible with your devices.
Compatibility: Digital cameras and other consumer electronics are designed to accept only specific memory cards. Even if a memory card fits into a slot on your camera or computer, it isn't necessarily compatible, and your device may not be able to read it. It is not possible to list all the makes and models and their cards, but most camera or cell phone product descriptions list which memory cards are compatible with each device.
Common memory card types: There are dozens of memory card formats, not all of which are still in production. These are some of the most common memory card formats currently used by consumer electronics:
Secure digital (SD or SDHC): SD memory cards can carry up to 4 GB of data. SDHC cards are similar in appearance, but they can store up to 32 GB or more. SDHC memory card slots are backwards-compatible with SD cards, but the opposite is not true for SD memory card slots.
MicroSD and MiniSD: These are smaller versions of SD cards, used for small devices like cell phones and MP3 players. Micro SD cards can be plugged into an adapter to be used in regular SD card slots as well.
Compact flash: Compact flash cards come in capacities as high as 100 GB. They aren't as common as SD cards, but they're gaining in popularity.
Flash memory: Flash memory is solid-state computer memory that doesn't require a spinning magnetic disc like your computer's hard drive. Flash memory cards, which include USB flash drives, are replacing hard disk drives in smaller devices, like MP3 players, cell phones, video game consoles and camcorders. USB flash memory is particularly popular as it can connect to any device with a USB port, but it does require a computer to act as intermediary.
Internal memory: Your camera or MP3 player may have a certain amount of internal storage, which is separate from any memory cards you may install. If you need more storage than internal memory provides, check to see if your device supports memory cards.
Memory card speed: The speed of a memory card is how fast it can exchange data with your camera's internal memory. The current convention is an "x" rating; for example, 1x equals a transfer rate of approximately 150 KB per second. Common digital memory card speeds include 40x (4-6 MB/second) and 80x (9-12 MB/second). Higher memory card speeds are most valuable when shooting pictures in quick succession.
NOR and NAND: These acronyms describe different ways that memory cards write and erase data. Early compact flash cards used NOR flash memory and were good for about 100,000 write-and-erase cycles, meaning you could rewrite memory card data only 100,000 times. After that, you had to get a new memory card. Newer flash memory cards use NAND logic, which is good for up to 1 million write-and-erase cycles.
Memory card care: Check your card and make sure it's going into the slot in the correct position. If inserted backwards or upside down, you might damage your camera, the card or both.