RAM

• RAM, or random access memory, is a volatile, fast memory. Volatile memory only operates when it is powered, so data stored in RAM is lost every time a computer is turned off.
  
  

DDR

• DDR stands for double data rate. This means that it can transmit data twice as fast as the older, single data rate RAM.
  
  

DDR1

• DDR1 RAM was the first type of double data rate RAM. It was a big advance over SDRAM, transferring data twice as fast as the computer's FSB, or front side bus.
  
  

DDR2

• DDR2 RAM also transfers data twice as fast as a computer's FSB speed, but it is compatible with computers with higher FSB speeds.
  
  

Advantages

• DDR2 RAM consumes less power than DDR1 RAM, so it operates at a lower temperature. RAM temperature increases with its speed, so DDR2 RAM can run faster than DDR1 RAM, while remaining cooler.