Almost all mobile phones, tablets and other devices use SD cards as a means of data storage. After the release of SD standard, SDHC and SDXC standard were launched as well. Even though the use of both SDHC and SDXC standards are the same, there are some differences between the two. SDHC cards have not exceeded the 32GB storage limit whereas theoretical storage limit in SDXC cards is around 2TB.
Speed is another difference between SDHC and SDXC. For fastest SDHC cards, speeds can reach a maximum of 12.5MBps. Of course there are minimum speeds as well. On the other hand, SDXC cards are much faster, with maximum speeds reaching 104MBps, more than 800% higher than SDHC cards. Devices such as HD video cameras and digital cameras with high resolution make use of SDXC cards.
The file system used by each of the card formats is another difference. SDHC cards use FAT32 file system whereas SDXC cards use exFAT file system. Even though exFAT file system is more recent than FAT32 file system, FAT32 is being used in most devices currently. For this reason, SDHC cards have an upper hand over SDXC cards. This trend may change in the future when card manufacturers start including the exFAT compatibility as well.
As far as actual size of the card is concerned, there are three options available in SDHC cards; standard, mini and micro. Standard SDHC cards are mostly used in DSLR cameras whereas mini and micro SDHC cards are mostly used in cell phones. On the other hand, SDXC cards come in only one size which is the standard size. The availability of options with respect to actual card size makes SDHC cards easy to use than SDXC cards.