These are universal steps and customers should refer back to the OEM or User manual for their device specific steps. T-Mobile does not recommend based on rated speed. The higher the class, the faster data can be consistently recorded, read, or transferred on the phone. For example if an SD card had a U rating of 1, the speed class would be 10 MB/s. This is usually a single digit and can be read as MB/s. The class is printed on SD cards as an even number inside a C.
Most smartphones can only take SD cards up to a certain size limit.
Refer to the following classifications to assist in determing the SD card that will work best with your smartphone.
If you see these problems with an SD card inserted in a smartphone, upgrade to a faster SD card. Advanced features like HD video recording, transferring files, or apps that use the SD card, it is likely to cause freezing, crashes, slowness, or errors. Using an SD card without the proper speed class may work for basic storage. SD card memory size and speed ratings vary by OEM.