What are the class speeds ratings of the SDHC?

The SD Association has created and defined several speed classes. SD speed class ratings specify minimum sustained write speed for SDHC cards write speeds as below.

• Class 2 > 2 MB/second
• Class 4 > 4 MB/second
• Class 6 > 6 MB/second

The SDHC Speed Class Logo to identify the performance class as below.

*. Image source: SD Association (http://www.sdcard.org/sdhc/index.html)