Memory card FAQ: all your questions answered



Memory cards are used in a range of devices, from cameras and camcorders to mobile phones, televisions and consoles. Knowing what type of memory card is right for you (and your particular devices) is becoming vitally important, and this is where we can help.

What is a memory card?

Memory cards are small devices (some no bigger than your thumbnail) that are used to store electronic data. This can be anything (depending on the device) from photos, music, movies, games, documents, programs and more. While cards come in a variety of shapes and sizes and are available for a variety of products, all memory cards do essentially the same thing — store data.

Memory cards, also referred to as flash memory, are essentially chips that allow users to write and rewrite data multiple times. Some of the key features of flash memory cards include their small size and the ability to retain data without a power supply. This allows them to fit into a variety of portable consumer devices.

What types of devices need memory cards?

Devices like the Nintendo Wii use SD cards. (Wii console SD card image by Evan Amos, public domain)

Memory cards first took off as the storage medium of choice in photography, with cameras dispensing with film rolls to instead rely on the much smaller and cost-effective memory cards. As well as digital cameras, memory cards are commonly used in mobile phones to store information like photos and music, as well as in camcorders to store video.

Memory cards are also used in other consumer electronic devices such as televisions, portable game devices, printers, DVD recorders and more. Many TVs come with card slots which allow users to see any stored photos on a big screen, while some printers allow you to print directly from images stored on a card.

While you can easily swap cards from one product to another, it's important to remember that different devices take different types of memory cards. If you already have a device that takes a memory card and want to buy more gear, make sure your intended purchase can take the same type of card.

What are the different types of memory cards available?

Over the past few years the number of different types of memory cards has reduced drastically, due to standardisation. The main types currently available include SD, Memory Stick and CompactFlash. Other, less common varieties in older devices include MMC, xD Picture Card and SmartMedia.

Secure Digital (SD) is the most widespread format, and come in various different capacities and speeds. Memory Stick is a proprietary format developed by Sony and as a result is found mainly in Sony devices. CompactFlash is a standard specifically developed for digital cameras and is now most commonly used in higher-end SLRs. The xD Picture Card is being phased out, a proprietary format developed by Fujifilm and Olympus.


Devices will usually only take one variety of memory card, although some cameras and camcorders have a single slot that accepts two different varieties of cards, such as Sony cameras, which generally take SD and Memory Stick. High end digital SLRs may also have two or more slots for different types of cards, such as the Nikon D300s, which has an SD and CompactFlash slot side-by-side.

Many formats also have sub-variants. SD, for example, also comes in miniSD and microSD (also known as TransFlash) forms, while Memory Sticks have the Memory Stick Pro Duo variants. While the underlying technology is the same, the size and form factor is vastly different in these variants.

Can I use the same card on other devices?

Even though the packaging suggests it's used for cameras, you can still use this SD card on other compatible devices. (Credit: Lexar)

The simple answer is yes, but with some caveats. As long as your different devices take the same type of card, you should be able to freely use the same memory unit in those different devices. If, for example, your mobile phone and laptop all take SD cards, then you'll be able to use the same SD card to store data, take pictures or transfer information.

You may not be able to access or use your stored data from one device to another, however. Individual devices may use a specific file structure when recording information onto a memory card, or they may use specific file format types. If a device is unable to browse a memory card's directory or cannot read a specific type of file format, then it won't be able to display or utilise something stored using a different device. Songs stored as MP3 files on a card, for example, can't be played on a device that doesn't have MP3 support.

Also worth noting is that older devices that use regular SD cards may not be able to read the newer SDHC and SDXC cards, even though the form factor is exactly the same.

How safe is the data stored on memory cards?

When it comes to the safety of your data, memory cards have some key advantages over other storage devices such as hard disks or CDs/DVDs. Memory cards are much more shockproof than other storage mediums. Since there are no moving parts in a memory card, they're much less prone to damage from movement, which can occur in a normal hard drive.

They're also much less fragile than a CD/DVD. The case of a memory card can easily take a scratch or two, while scratches on the underside of a CD or DVD will most often result in data loss or an unreadable disk. Since memory cards are physically so small, perhaps the greatest risk of data loss lies with losing the entire card itself, rather than by some other accident.

SanDisk's all-in-one reader can take all major types of memory cards. (Credit: SanDisk)


Most portable devices come with cables to link directly to a PC or laptop, allowing you to transfer any images or data stored on your memory card. If you don't have your device or cable with you, however, there are other alternatives.

The majority of new PCs and laptops are now being sold with built-in card readers. These allow you to slide your card directly into the computer, from which you can access any data stored on the card. There are also stand-alone card readers you can purchase. These card readers can usually read more than one type of card, which is handy if you've got several devices with different memory units.

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by David Katzmaier