microSD cards fast enough for running Android apps will be marked with the new A1 symbol25
This is useful for owners of Android Marshmallow and later devices, as it was in late 2015 that Google added adoptable storage support to the operating system. It requires users to own or buy a microSD memory card before running a benchmark tests, and alas, some microSD cards may not pass the test, because they were developed for optimal image and video capture instead of application running. The App Performance Class symbol will give product manufacturers a way to communicate its app-running optimization before buying a microSD card.
Upon release, the SD Association has introduced the first and most basic App Performance level, which is App Performance Class 1, or A1. The SDA will introduce higher App Performance levels as market needs evolve. microSD memory cards that display the A1 symbol (pictured below) meet, or exceed, the following recommended speeds:
- Random Read Input-Output access Per Second (IOPS) of 1500
- Write IOPS of 500
- Sustained Sequential performance of 10MB/s.
source: SD Association (Marketwire) via Android Authority