The SD Association has announced (PDF) a new specification called ‘Application Performance Class’ that should make clear that Android applications run smoothly from micro SD cards with the logo.
Many Android phones can extend their storage capacity with an micro SD card. Since Android 6.0 Marshmallow it’s also possible to run apps from SD cards. This does require a minimum performance and therefore the SD Association now marks suitable SD cards with the “A1-Class”.
SD cards are already categorized in performance classes like Class 10, UHS1 and UHS3. The fast UHS cards will have no issues running apps but to make it even easier, the SD Association now introduces the A1-Class. The ‘A’ means App in this case.
A SD card that is labeled with A1 is specified to meet or exceed random reads of 1500 IOPS, random writes of 500 IOPS and sustained sequential performance of 10MB/s.
In case future smartphones will demand higher specifications, the SD Association will add a A2 Class.