RAM(Random Access Memory) 

There are two basic types of RAM :

(i) Dynamic Ram
(ii) Static RAM
 RAM is the best known form of Computer Memory. The Read and write (R/W) memory of a computer is called RAM.  RAM holds data and processing instructions temporarily until the CPU needs it.
Dynamic RAM : loses its stored information in a very short time (for milli sec.) even when power supply is on. D-RAM’s are cheaper & lower.
Static RAM : It uses a completely different technology. S-RAM retains stored information only as long as the power supply is on. Static RAM’s are costlier and consume more power. They have higher speed than D-RAMs