Tags : #type of memory card classes, #speed classes types, #ultra high speed classes types, #micro SD card classes, #type of mobile memory cards
1. Speed Classes
Speed Class is a minimum speed based on a worst case scenario test. The Speed Class is important for video mode or camcorders, where the device is actually saving a steady stream of data. The resolution and format of the video determines the amount of steady stream data. This translates to a minimum speed you need to guarantee that the video captured on the cards is recorded at an even, sustained rate with no dropped frames (which would result in lost data and choppy playback).
The current SDHC specification defines Class 2, 4, 6, 8 and 10 as follows:
Class
|
Minimum Speed
|
2
|
2MB/s
|
4
|
4MB/s
|
6
|
6MB/s
|
8
|
8MB/s
|
10
|
10MB/s
|
2. Ultra High Speed (UHS) Speed Classes
UHS Speed Class was introduced in 2009 by the SD Association and is designed for SDHC and SDXC memory cards. UHS utilizes a new data bus that will not work in non-UHS host devices. If you use a UHS memory card in a non-UHS host, it will default to the standard data bus and use the "Speed Class" rating instead of the "UHS Speed Class" rating. UHS memory cards have a full higher potential of recording real time broadcasts, capturing large-size HD videos and extremely high quality professional HD.
UHS Class
|
Minimum Speed
|
1
|
10MB/s
|
| 3 | 30MB/s |
