Which of the following is fastest memory?

The Correct Answer is "Cache Memory".

Important Points

Cache Memory :

• Cache Memory is a special very high-speed memory.
• It is used to speed up and synchronizing with a high-speed CPU. Cache memory is costlier than main memory or disk memory but economical than CPU registers.
• Cache memory is an extremely fast memory type that acts as a buffer between RAM and the CPU.
• It holds frequently requested data and instructions so that they are immediately available to the CPU when needed.
• Cache memory is used to reduce the average time to access data from the Main memory.

Additional Information

Secondary Memory​ :

• It is non-volatile, i.e. it retains data when power is switched off.
• It is large capacities to the tune of terabytes.
• It is cheaper as compared to the primary memory.
• Depending on whether the Secondary memory device is part of the CPU or not, there are two types of secondary memory – fixed and removable.

 Auxiliary Memory :

• Auxiliary memory is the non-volatile memory lowest-cost, highest-capacity, and slowest-access storage in a computer system.
• It is where programs and data kept for long-term storage or when not in immediate use.
• Such memories tend to occur in two types-sequential access (data must access in a linear sequence) and direct access (data may access in any sequence).
• The most common sequential storage device is the hard disk drives, whereas direct-access devices include rotating drums, disks, CD-ROMs, and DVD-ROMs.
• It used as permanent storage of data in mainframes and supercomputers.

Virtual Memo :

• A computer can address more memory than the amount physically installed on the system.
• This extra memory is actually called virtual memory and it is a section of a hard disk that's set up to emulate the computer's RAM.
• The main visible advantage of this scheme is that programs can be larger than physical memory.
• Virtual memory serves two purposes.
  • First, it allows us to extend the use of physical memory by using the disk.
  • Second, it allows us to have memory protection because each virtual address is translated to a physical address.