Instead of going for an SD card, what if you tried a microSD memory card next time you're looking to upgrade a portable device?

This diminutive standard works with hundreds of mobile phones, multimedia players and GPS systems, and is also compatible with most digital cameras, provided you use the special adapter that is usually provided as standard.

Be careful, though, as our tests show that these tiny cards aren't always suitable for the demands of high-powered digital cameras.

Here are the cards we looked at:

• Verbatim Micro SD 2 GB

• Dane-Elec Micro SDHC 4 GB Class 4

• PNY Micro SDHC Mobility Pack 4 GB

• Verbatim Micro SDHC 4 GB Class 6

The "Class" of a memory card is supposed to be a guarantee of a minimum speed level, but as ever, it's worth taking manufacturers' claims with a pinch of salt.

During this round-up, we saw products that barely met the minimum speed for their class alongside others than went way beyond the target data transfer rates.

> Product Survey: Memory Cards