The Facts

• SD card transfer rates for the basic cards range from 2 to 5 megabytes per second, according to EE Times Asia. High speed cards can get about 20 megabytes per second.
  
  

Function

• SD card transfer rates degrade over time because SD cards store information in blocks. The more you write to your SD card, the more these chunks fragment and slow down the read/write process.
  
  

Solution

• The SD Association has different classes of cards that guarantee a certain minimum transfer rate. Class 4 and 6, for example, offer the minimum transfer rate needed to record high definition video in real time.
  
  

Tip

• The SD Card Association recommends that consumers look for the class logo on their SD cards to make sure they are appropriate for the devices or applications they use.