Capacity
This is the most straightforward feature. First, “SD” stands for “secure digital.” MicroSD cards are available in SDHC and SDXC varieties. SDHC stands for “secure digital high capacity,” and SDXC stands for “secure digital extended capacity.” This should tip you off as to what the difference is between the cards. SDHC microSD cards range in storage capacity from 4GB to 32GB. SDXC cards start at 32GB and can reach a maximum capacity of 2TB. Which card you choose depends on how much storage you need. You’re going to want the largest card you can afford if you take lots of photos, have tons of music or like to carry a bunch of movies and TV shows in your pocket. Of course microSD cards range in price depending on the capacity. So before you fork over your hard-earned cash on a card, make sure that your Android device can support the card. Generally speaking, less expensive Android devices only support SDHC cards, meaning you’ll be limited to 32GB max. Exactly how much storage you need will be determined by your usage, but generally speaking, anyone with a large media library, whether that is photos, videos or music, will benefit from a larger capacity card. Finally, the capacity of the card does not effect the quality of the digital files stored on it. Simply put, the difference between these cards begins and ends with the storage size available to you.
Class
Different SD cards have different read/write speeds that can impact performance. SD card manufacturers use “speed classes” to measure the read/write speed of the card. Cards are given one of four classifications: 2, 4, 6 and 10. The numbers assigned to the card correspond to the minimum transmission speed of the card. If a card is class 2, it has a minimum transmission speed of 2 Megabytes per second (MB/s). Class 4 has a minimum speed of 4 MB/s, class 6 has a speed of 6 MB/s, and so on. The speed class of the card is always directly on the card’s label, signified as a number (2, 4, 6, 10) inside the letter “c.” In addition to these standard speed classes, there are two Ultra High Speed (UHS) classes. UHS cards are significantly more expensive and are designed to be used with UHS compatible devices. UHS cards have a classification of either 1 or 3, with 1 signifying a minimum speed of 10 MB/s and 3 a minimum speed of 30 MB/s. There aren’t many Android devices that support UHS microSD cards, but they will become commonplace in the future.
Conclusion
The best microSD card for you is going to depend on how you use your phone. If you only want to make room for music, you probably don’t need the fastest card on the market. However, if you’re shooting photos in RAW format or recording in 4K, you’re going to need a better performing (and more expensive) card. What type of microSD card do you use in your Android device? Have you tried different microSD card speeds? What has been your experience with the different speeds available? Let us know in the comments!