Memory Cards Speed Class

MEMORY CARDS

Memory Cards Speed Class

In 2006 the SD Card Association defined a categorization according to the minimum writing speed called Class

 

Classification of cards according to their writing speed
Class24610
Minimum write rate (Mo/s)24610

 

UHS (Ultra High Speed)

 

In addition to these classes, there are the UHS-I (Ultra High Speed I) specifications, whose RAM technologies used allow a higher theoretical average throughput, depending on the device using the card.

The second version of this UHS-II standard (November 2013) further increases the average theoretical throughput. adding a second row of pins to the card.

 

Pin LayoutPin layout 1Pin layout 2
SD Bus InterfaceHight SpeedUHS-I
Hight Speed
UHS-II
UHS-I
Hight Speed
UHS-III
UHS-II
UHS-I
Hight Speed
2TB
(exFAT)
SDXCSDXC 1SDXC 2SDXC 3
32GB
(FAT32)
SDHCSDHC 1SDHC 2SDHC 3
2GB
(FAT12/16)
SD   
 25MB/s104MB/s312MB/s624MB/s

 

 

Speed Classes

Minimum Sequential Write Speed according to the logo(s)
Minimum Sequential Write SpeedSpeed Classes
Speed ClassUHS Speed ClassVideo Speed Class
90 MB/sec  V90
60 MB/sec  V60
30 MB/sec UHS Class 3V30
10 MB/secClass 10UHS Class 1V10
6 MB/secClass 6 V6
4 MB/secClass 4  
2 MB/secClass 2