Memory cards: All your questions answered

Memory card shopping tips

1. Don't buy the wrong memory card type
Make sure you know exactly what type of memory card your digital camera, mobile phone, PDA or games device uses before you hand over your hard earned cash. Devices will more often than not be only compatible with one type of memory card, which means you're stuck if you inadvertently buy the wrong one. Check your device to see exactly what you'll need.

Sony's PSP comes packaged with a 32MB Memory Stick Duo, but you'll almost certainly need to buy a larger card.

2. Don't rely on the device's included memory
Some consumer devices now come with bundled memory cards, allowing consumers to use the product straight out of the box. But in most cases, these bundled cards are at the low end of the capacity spectrum, meaning you won't be able to store too much information on them before having to free up some space. Sony's PSP, for example, comes bundled with a 32MB Memory Stick Pro Duo - but that will get quickly eaten up by a few game saves, songs or photos. An entire movie would not fit on the included card. Buying a larger capacity card means being able to store more and having to swap cards less often.

3. Let your hardware determine the size of memory card you buy
Memory cards with large capacities are not only more convenient, they're practically mandatory for some devices. For example, digital cameras with high megapixel ratings chew up more memory space per shot. On a 32MB memory card, you'll be able to fit roughly 16 shots from a 4-megapixel camera, while you'll only be able to fit 10 shots from a 6-megapixel camera. When it comes to cameras, the rule is the higher the megapixel count, the greater the memory card capacity you'll need.

Larger memory cards are also suited for multimedia devices such as PDAs. This allows you to store more messages, documents, music, movies and photos. Considering that an average song takes up about 4MB of space and movies take up to a couple of hundred megabytes, you can see how easily a multimedia device can fill up a memory card's space.

The 7.1-megapixel Sony Cyber-shot DSC-T10 comes with 56MB of built-in memory.

4. Don't forget about memory card speed
Apart from capacity, the main specification you'll probably come across when shopping for a memory card is its speed rating. Speed ratings are usually expressed either as writing speed per second (for example, 10MB/sec or 20MB/sec) or as a performance multiplier (for example, 60X or 80X). As the term implies, this rating measures how quickly information can be written or read on the card.

Faster speed ratings means your memory card is quicker to recover after data is written to it. This is especially important for digital photography - having a fast memory card means you're able to take another shot quicker than usual, particularly for higher megapixel models.

But while speed ratings are important, keep in mind that it's a two way street. Not only does your memory card need to be fast, but the device it's paired with also needs to be able to write/read at a similar speed to maximise benefits. Some cards claim up to 20MB/second speed, but only a very few devices (such as high end digital SLRs) are able to work at the same rate. If your digital device isn't top of the line, then chances are you won't need (or be able to utilise) the extra dash of a high speed memory card.

5. Don't forget that not all memory cards are the same
You'll find plenty of manufacturers out there selling memory cards, all with similar looking products and claiming similar capacity and performance. Not all memory cards are equal, however - cards can be made from varying quality components and manufacturing standards. If you've bought a cheaper generic card before and have had no problems, then by all means stick with it. Otherwise, stay with cards from recognised brands sold through authorised dealers.

6. The more memory cards the merrier
If you're going away on holidays (or are just an avid user of technology), then there's no reason to stop at just one memory card. The last thing you want is to run out of room on your digital camera halfway through your once-in-a-lifetime overseas trip.