There's no limit to the size. Speed is limited to around ~50MB/s. The flash and controller used within an MicroSD card is more important than the rating. Usually good MLC flash can write at full speed where as cheap TLC flash can only write at around 20MB/s max. Typical Sandisk Ultra or Samsung EVO use TLC and expensive Samsung Pro and Sandisk Extreme use MLC.
Comments
There's no limit to the size. Speed is limited to around ~50MB/s. The flash and controller used within an MicroSD card is more important than the rating. Usually good MLC flash can write at full speed where as cheap TLC flash can only write at around 20MB/s max. Typical Sandisk Ultra or Samsung EVO use TLC and expensive Samsung Pro and Sandisk Extreme use MLC.