New Standards for SD Cards

The SD Association, which manages the development of SD memory cards, has announced two new logos to explain to consumers what speeds their new SDHC and SDXC cards are capable of.  Look out for a capital 'I' and a capital 'U' with a 1 inside of it ...

The two new standards are aimed at identifying new classes of card, just like the Class 10 label which was introduced to cover cards that were easily surpassing the requirements for the earlier Class 6 standard.

The difference here is that the new symbols are less intuitive.  The old-fashioned class system had one clear advantage over the incomprehensible 'x' system still used for CF cards: it was easy to understand.  Class 6 cards could transfer data at 6 MB/s, Class 10 cards at 10 MB/s and so on, based on using large files—moving multiple smaller files is always slower.

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The new Ultra High Speed I logo is for cards that 'offer the fastest bus-interface speeds available today, capable of supporting data transfer speeds up to 104 MB/s.'  The problem, though, is that the bus speeds isn't that relevant.  If the chip in the card can't suck up more than 30 MB of data a second, then it will be the write speed of the card itself that's important, regardless of fast the bus is.  The same thing is true of memory card readers, which also be able to carry the 'I' logo when they're compatible with new 'UHS-I' cards.

Right now, the current generation of chips struggles to reach the maximum speed allowed by the bus.  The fastest currently available SDHC card, the SanDisk SDHC Extreme Class 10, tops out at 18 MB/s.

The second new logo, which represents Speed Class 1, can be displayed by products 'with a performance option designed to support real-time video recording.'  And there you were thinking that any Class 10 card should be able to hack the 5-6 MB/s that a Full HD stream involves, meaning it can record video in real time on any of today's camcorders or digital cameras ...  Well, we did too!

These two new logos are set to appear on SD cards but we're not really sure what they're going to do to help consumers decide.  We would have preferred to meet the arrival of new speeds with an extension of the class system.  Class 15 could be launched right now, and why not add extra classes to support increased bus speeds?

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