Key difference: RAM is a primary data storage device that stores data that is required by the computer to execute operations. It is a part of hardware that stores operating system’s application programs and currently running processes. CPU, on the other hand, is the hardware within the computer that carries out the instructions of a computer program.

Both Random-Access Memory (RAM) and Central Processing Unit (CPU) are primary devices that are used in electronics, most commonly in computers. RAM is a primary data storage device that stores data that is required by the computer to execute operations. It is a part of hardware that stores operating system’s application programs and currently running processes. CPU, on the other hand, is the hardware within the computer that carries out the instructions of a computer program.

The comparison between RAM and CPU is as follows:

RAM: Random-Access Memory is a volatile memory used for data storage on a computer. The name states the memory can be accessed in a random order, without having to alter or read other data. This stores data that is used by programs, however once the computer is shut down, the data is wiped out. RAM operates much faster that ROM. It comes in the form of microchips of different sizes such as 256MB, 512MB, 1GB, 2GB etc. Computers are designed, so that RAM can be increased up to a certain capacity.

RAM has two types: Static RAM (SRAM) or Dynamic RAM (DRAM). In SRAM, data is held in a flip-flop form, where each flip-flop holds a bit of memory. This data does not need constant refreshing is fairly faster than DRAM, however it is expensive and is only used as a cache in a PC. DRAM has memory cells paired with a transistor and capacitor requiring constant refreshing.

CPU: A central processing unit (CPU) is the hardware within a computer system that carries out the instructions of a computer program by performing the basic arithmetical, logical, and input/output operations of the system. It is also called a central processor unit, or more commonly a processor. However, many mistakenly use the term CPU to refer to the housing unit that stores all of the computer’s hardware, whereas, in actuality it is just the small processor chip that runs the computer’s programs.

In large computers, the CPUs require one or more printed circuit boards. However, in personal computers and small workstations, the ones which most of us use, the CPU is housed in a single silicon chip called a microprocessor.

The fundamental function of a CPU is to run or execute a program. A program is essentially a sequence of stored instructions, which is represented by a series of numbers that are kept in some kind of computer memory. CPUs follow a four step process in their operation: fetch, decode, execute, and writeback.

In addition to executing a program, the CPU is also responsible for keeping an eye over system functions, for executing scripts, and for making complex calculations, which are often used in software rendering. CPUs also initiate transfer of large blocks of data, as well as read or write data to and from peripheral devices, such as CDs, DVD, USB drives, etc.

Since, the CPU is responsible for practically all the processes running in the computer, it is only acceptable to state that the faster the CPU is, the faster the applications can run. However, a very large CPU is also not necessary for most home computers, as many of us do not run that many programs at a single time.

There are two typical components of a CPU:

• The arithmetic logic unit (ALU), which performs arithmetic and logical operations, and
• The control unit (CU), which extracts instructions from memory and decodes and executes them; calling on the ALU for help when necessary.

Image Courtesy: brandolution.com, techiwarehouse.com