Only focus on the cheap price SD card instead of distinguishing the high-speed and low-speed isn’t a smart idea because using a low-speed SD card on a high-speed device can easily destroy the SD card.
To distinguish which is a high-speed SD card and which is a low-speed SD card, you need to understand the three signs on the SD card. You can judge whether it is a high-speed card or a low-speed card through the following three symbols.
The first one is the Class value. There are four levels of C2-C10 on the SD card.
C2 means that the writing speed is 2MB per second, which is suitable for the most common low-definition video.
C4 indicates that the write speed is 4MB per second, which is suitable for high-definition TVs.
C6 means that the writing speed is 6MB per second, which is suitable for continuous shooting with professional cameras.
C10 means that the writing speed is 10MB per second, which is suitable for devices with higher definition or higher requirements for image quality.
C2, C4, and C6 are generally called ordinary cards, which are low-speed cards, and C10 is generally recognized as high-speed cards.
The second one is UHS value. UHS means ultra-high-speed interface, and currently you can see two levels of U1 and U3.
U1 indicates that the write speed is 10MB.
U3 indicates that the write speed is 30MB.
If you see one of the logos on the SD card, it means that the card is a high-speed card. U1 can meet the high-speed continuous shooting of professional cameras, and U3 can meet the 4K video playback and recording. The recording of the home 1080p camera requires a U3 SD card, which is easy to burn with U1.
The third, HC and XC values. HC is a High Capacity memory card, and XC is a Xpanded Capacity memory card.
The capacity of HC is 2G to 32G, and the file system is generally FAT32 format.
The capacity of XC is 64G to 2T (2048G), and the file system is exFAT format.
XC is not an improvement on the original basis, but an upgraded product. So XC is compatible with HC, and HC is not compatible with XC, and the transmission can be up to 300MB per second. So even the common XC SD card, the lowest speed is also the start of C10 and U1.