If you’ve noticed how memory card capacities have increased, you’ve also probably noticed that the smaller micro cards have mirrored the changes as well. Since we have SD and SDHC memory cards, we also have microSD and microSD HC cards. Apart from the size, the micro SD and micro SD HC cards are identical to their larger counterparts. So the differences betweed microSD and microSD HC are the same as the differences between SD and SDHC cards.
Of course, the most prominent difference between microSD and microSD HC cards is capacity. microSD cards, like its bigger brother, only comes up to a maximum capacity of 4GB. One the other hand, microSD HC memory cards starts from 4GB and maxes out at a whooping 32GB. This capacity limits are not because of hardware limitations but are because of how the space is partitioned and how it is addressed and accessed.
Because they are electrically compatible, it is trivial for microSD HC card readers to achieve backwards compatibility with the older microSD cards. But this is not the case when you use a microSD HC card on a microSD card reader. Because of the changes in how the storage capacity is calculated. microSD card readers are not capable of determining how large a microSD HC card is and cannot read or write files to the card.
microSD is an old standard that is no longer being used that much. microSD HC has already replaced it in just about all areas. But if you still have old microSD cards, you can still use them with newer devices as long as the lower memory capacity is sufficient for your needs. There are even small card readers that instantly turn your microSD card into a USB flash drive, which you can use as back-up for small but important files or for moving files from one computer to another. The only trouble you will experience is if you have an old device that you are buying memory for. If it doesn’t support microSD HC memory cards, then you are stuck with microSD cards. You should check if your device does support microSD HC, or better yet, bring the device to the store so that you can be sure of your purchase before leaving the store.
Summary:
microSD and microSD HC cards are identical to their larger counterparts
microSD HC cards have higher capacities than microSD cards
microSD HC cards cannot be read in microSD only capable devices