• SD and CF cards are most commonly used for digital camera storage.sd slot image by TEA from Fotolia.com
  
  Secure digital (SD) cards and compact flash (CF) cards are two common flash memory standards. Both cost about the same amount of money and are compatible with a wide range of devices, such as digital cameras, computers and printers. However, there are some notable differences between the two card standards you should be aware of before investing in either technology.
  
  

Design

• SD cards are much smaller than CF cards.film can and sd card image by dwags from Fotolia.com
  
  The most obvious difference between compact flash and SD memory cards is size. An SD card is about the size of a postage stamp and has nine pins. Compact flash cards are much bigger because they have 50 pins. A CF card is about half the size of a playing card and nearly four times as thick as SD memory.
  
  Compact flash cards have a built-in memory controller. This reduces the processing load of the device it is plugged into, but makes little difference in real-world use. Although SD cards might lack a memory controller, they do contain hardware for encrypting data. Most devices do not take advantage of this technology.
  
  

Performance and Capacity

• Compact flash cards have a theoretical maximum capacity of 137GB, whereas the official SD card specifications only support up to 2GB. Although manufacturers have released larger SD cards, they are not available in capacities as high as compact flash cards.
  
  In real-world scenarios, SD cards are just as fast as CF memory. Other factors, such as the memory card reader you use and the speed of the device you plug a card into, play a much larger role in the speed of the card. In theory, however, CF cards have the potential to reach higher speeds because they have more pins.
  
  

Compatibility

• Adapters are available that let CF devices use SD cards.blue cf image by Randy McKown from Fotolia.com
  
  SD and CF cards work with thousands of digital cameras, computers and other devices. However, SD cards are compatible with a greater number of devices overall.
  
  For instance, SD memory is the preference of newer cameras because of its small size. On the other hand, many high-end DSLR cameras do not have SD card slots. However, adapters are widely available that plug into the larger CF card slot and allow the user to plug in an SD card. CF cards are too large to fit in an SD slot even with an adapter. Finally, more computers contain memory card readers for SD memory than CF memory.