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SD Cards to be Rated for App Performance

A new classification system is being introduced for SD cards.


The Secure Digital Association is introducing a new system for rating how well different SD memory cards will work with mobile applications. The first such class is called A1, and is defined as part of SD Specification 5.1, which was just released. Spec 5.1 details standards for storing and running apps on mobile devices while providing storage for photos, videos and other types of files.

“With its consumer-friendly symbol, App Performance Class eliminates buyers’ frustration with identifying app-running compatibility on their Android devices and microSD memory cards,” said Brian Kumagai, SD Association president. “Matching the App Performance Class symbol with your mobile device requirements simplifies the process and continues the SD tradition of matching your memory card to your device.”


App performance class A1 required the memory card to have sustained sequential performance of 10 MB a second. It also requires 1500 random read IOPS (input/output operations per second) and 500 random write IOPS. At least one of these requirements isn’t too stringent. UHS Speed Class 1 and regular Speed Class 10 already achieve the sustained sequential performance requirement. More classes with higher demands will follow A1 later, as the market evolves.

However, the sequential performance rating isn’t the one that really matters. SD cards have evolved from a medium used purely for storage, to one that is used as flash memory for running applications, and being able to quickly read and write is crucial in providing decent performance. Some cards may not be up to the task, and now you’ll be able to tell.

source: SD Association

David F.
A grad student in experimental physics, David is fascinated by science, space and technology. When not buried in lecture books, he enjoys movies, gaming and mountainbiking

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