Memory (Eng. Random Access Memory, RAM, random access memory, RAM, comp. Zhargy. Memory, RAM) - a volatile part of the computer's memory, which temporarily stores the input, output and intermediate data processor program. The most common types of DIMM and SIMM. 

Exchange of data between the processor and memory is made: 

through ultra-fast memory level 0 - registers in the ALU, or if there is a hardware processor cache - through cache. 
Contained in modern semiconductor memory and stored data is available only when memory is energized. Turning off the power of RAM, even short-term, leads to distortion or complete destruction of stored information. 

Energy saving modes allow computer motherboard turn it into a "sleep", which significantly reduces the power consumption of the computer. In "Sleep" power RAM is disabled. To save the contents of RAM, in this case, before powering down, the contents of RAM is written to a special file, usually located on the hard disk or hard drive partition. For example, in Windows XP, this file hiberfil.sys, OS family Unix - special swap-section). 

In the general case, the RAM contains programs and data running OS and applications, and user data from these programs, so the amount of memory depends on the number of tasks that can simultaneously perform computer running.