Buyer's Guide Until the day when broadband is much faster, all devices have wireless internet access and sync'n'store services such as Dropbox or Google Drive are ubiquitous, memory cards will remain the most convenient general-purpose, pocketable storage.

They help everyone to move documents, photos, music and videos around safely and simply. But which to choose?

Memory cards come in half a dozen different shapes and many more capacities and speeds. They are the de facto portable storage standard, but selecting the best match to the gear that uses them is not as simple as it might seem.

It is not just a question of buying a Memory Stick for a Memory Stick socket, or a Secure Digital (SD) card for an SD slot. There are ranges of different capacities and different speeds. You don’t need the same speed for saving audio in a media player as you do for saving video in a camera.

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Card types

Some memory card types have fared much better than others over the years. SmartMedia has completely died away and xD-Picture Card (xD), only used by Fujifilm and Olympus, is supported by very few new cameras.

CompactFlash mainly survives because high-end digital SLR cameras from the likes of Canon and Nikon still use them.

MultiMediaCards, which have the same physical dimensions as SD, have been subsumed and offer no real advantage over SD.

SD and Sony's Memory Stick between them, in their various guises, are by far the most popular types of card. SD is particularly so since it is an open standard backed by dozens of companies, including Samsung and a host of others.

More recently, the high-capacity SDHC and extended capacity SDXC cards have enabled storage up to 32GB and 2TB, respectively, although the 1TB and 2TB cards are not yet readily available.

The SD card has spawned Mini SD – now a dying breed – and Micro SD variants, mainly used in smaller devices such as smartphones and media players. Memory Stick is available in Duo, Pro Duo and Pro-HG Duo, as well as its basic form.

All cards are available in different capacities and some also in different speed grades; the choice is, of course, dictated by the device you are using. Few bits of kit can take more than one type of card, with the exception of multi-card readers in PCs and printers.

If your computer lacks a certain kind of memory card slot, USB-connectable adapters are commonplace.

Capacities

As memory technology has advanced, card capacities have grown from kilobytes (KB) through megabytes (MB) to gigabytes (GB). Specifications are already in place for terabyte cards.

Typical capacities today range from 1GB up to 32GB, with 64GB, 128GB and 256GB available for specialist uses.

The best advice is generally to go for the highest capacity you can afford, but there’s a proviso. If you have the cash for, say, a card that can store four hours of video or for two that can store two hours each, the two-hour ones might give you more flexibility.

You might find it useful to categorise your videos and keep one card for each category. It could help with the data housekeeping, and also prevent you losing all your data if a camera goes missing.

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