The SD Association recently took the wraps off SD Specification 6.0 which includes the A2 (Application Performance Class 2) standard, designed for newer Android devices with the capability of using microSD cards as Adoptable Storage. Adoptable Storage is a new Android feature which rolled out with Android 6.0 Marshmallow allowing SD cards to be used as internal storage.
According to the announcement, A2 class memory cards will be required to include features such as command queue, cache, and self-maintenance as well as deliver performance meeting or exceeding random read performance of 4000 IOPS, random write performance of 2000 IOPS, and sustained sequential performance of 10MB/s. For reference, this is more than double the random performance requirement of the A1 specification, which specifies a random read performance of 1500 IOPS, random write performance of 500 IOPS and sustained sequential performance of 10MB/s.
More information about the A2 specification is available at the SD Association’s website here.