SD Speed Class/UHS Speed Class/Video Speed Class

Greater Performance Choices

There are three kinds of Speed Classes, “Speed Class”, “UHS Speed Class” and “Video Speed Class.”

As a characteristic of flash memory, actual transfer speed varies. Variable speeds are difficult to reliably record streaming content such as video because it requires a constant writing speed. All Speed Classes provide the constant speed necessary for video recording by designating a minimum writing performance so that minimum and constant speed could be achieved for camcorders, video recorders and other devices with video recording capabilities under the conditional write operation specified in the standard.

SD Standard SDHC Standard SDXC Standard SDUC Standard
Capacity up to 2GB more than 2GB

up to 32GB

more than 32GB

up to 2TB

more than 2TB

up to 128TB

File System FAT 12, 16 FAT 32 exFAT exFAT
SD Logo SD SDHC SDXC SDUC
Form Factor Size SD 32 x 24 x 2.1 mm
microSD 11 x 15 x 1.0 mm

Speed Classes
Normal
Speed
mode
C2, C4, C6
High
Speed
mode
C2, C4, C6, C10,

V6, V10

UHS-I

mode

C2, C4, C6, C10

U1, U3

V6, V10, V30

UHS-II

mode

C4, C6, C10

U1, U3

V6, V10, V30, V60, V90

UHS-III

mode

C4, C6, C10

U1, U3

V6, V10, V30, V60, V90

SD Speed Class

SD Speed Class

Video Format

Video Format