Central processing unit

EDVAC, one of the first stored-program computers
IBM PowerPC 604e processor
Fujitsu board with SPARC64 VIIIfx processors
CPU, core memory and external bus interface of a DEC PDP-8/I, made of medium-scale integrated circuits
Inside of laptop, with CPU removed from socket
Block diagram of a basic uniprocessor-CPU computer. Black lines indicate data flow, whereas red lines indicate control flow; arrows indicate flow directions.
Symbolic representation of an ALU and its input and output signals
A six-bit word containing the binary encoded representation of decimal value 40. Most modern CPUs employ word sizes that are a power of two, for example 8, 16, 32 or 64 bits.
Model of a subscalar CPU, in which it takes fifteen clock cycles to complete three instructions
Basic five-stage pipeline. In the best case scenario, this pipeline can sustain a completion rate of one instruction per clock cycle.
A simple superscalar pipeline. By fetching and dispatching two instructions at a time, a maximum of two instructions per clock cycle can be completed.

Electronic circuitry that executes instructions comprising a computer program.

- Central processing unit

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Graphics processing unit

Specialized electronic circuit designed to manipulate and alter memory to accelerate the creation of images in a frame buffer intended for output to a display device.

Components of a GPU
Atari ANTIC microprocessor on an Atari 130XE motherboard
NEC μPD7220A
The IBM 8514 Micro Channel adapter, with memory add-on.
VGA section on the motherboard in IBM PS/55
Tseng Labs ET4000/W32p
S3 Graphics ViRGE
Voodoo3 2000 AGP card
The ATI HD5470 GPU (above) features UVD 2.1 which enables it to decode AVC and VC-1 video formats
The position of an integrated GPU in a northbridge/southbridge system layout
An ASRock motherboard with integrated graphics, which has HDMI, VGA and DVI outs.

Their parallel structure makes them more efficient than general-purpose central processing units (CPUs) for algorithms that process large blocks of data in parallel.


Auxiliary device used to put information into and get information out of a computer.

A human computer, with microscope and calculator, 1952

The term peripheral device refers to all hardware components that are attached to a computer and are controlled by the computer system, but they are not the core components of the computer, such as the CPU or power supply unit.

System on a chip

Integrated circuit (also known as a "chip") that integrates all or most components of a computer or other electronic system.

AMD Am286ZX/LX, SoC based on Intel 80286
Microcontroller-based system on a chip
SoC design flow

These components almost always include a central processing unit (CPU), memory interfaces, on-chip input/output devices, input/output interfaces, and secondary storage interfaces, often alongside other components such as radio modems and a graphics processing unit (GPU) – all on a single substrate or microchip.


Small computer on a single metal-oxide-semiconductor (MOS) VLSI integrated circuit (IC) chip.

The die from an Intel 8742, an 8-bit microcontroller that includes a CPU running at 12 MHz, 128 bytes of RAM, 2048 bytes of EPROM, and I/O in the same chip
Two ATmega microcontrollers
A PIC 18F8720 microcontroller in an 80-pin TQFP package
Die of a PIC12C508 8-bit, fully static, EEPROM/EPROM/ROM-based CMOS microcontroller manufactured by Microchip Technology using a 1200 nanometer process
Die of a STM32F100C4T6B ARM Cortex-M3 microcontroller with 16 kilobytes flash memory, 24 MHz central processing unit (CPU), motor control and Consumer Electronics Control (CEC) functions. Manufactured by STMicroelectronics.

A microcontroller contains one or more CPUs (processor cores) along with memory and programmable input/output peripherals.

Computer program

Sequence of instructions in a programming language that a computer can execute or interpret.

Lovelace's description from Note G.
Zuse Z3 replica on display at Deutsches Museum in Munich
Glenn A. Beck is changing a tube in ENIAC.
Switches for manual input on a Data General Nova 3, manufactured in the mid-1970s
A VLSI integrated-circuit die.
IBM's System/360 (1964) CPU wasn't a microprocessor.
Artist's depiction of Sacramento State University's Intel 8008 microcomputer (1972).
The original IBM Personal Computer (1981) used an Intel 8088 microprocessor.
The DEC VT100 (1978) was a widely used computer terminal.
Prior to programming languages, Betty Jennings and Fran Bilas programmed the ENIAC by moving cables and setting switches.
"Hello, World!" computer program by Brian Kernighan (1978)
A computer program written in an imperative language
A diagram showing that the user interacts with the application software. The application software interacts with the operating system, which interacts with the hardware.
A kernel connects the application software to the hardware of a computer.
Physical memory is scattered around RAM and the hard disk. Virtual memory is one continuous block.
NOT gate.
NAND gate.
NOR gate.
AND gate.
OR gate.
A symbolic representation of an ALU.

The central processing unit will soon switch to this process so it can fetch, decode, and then execute each machine instruction.

Vector processor

Cray J90 processor module with four scalar/vector processors

In computing, a vector processor or array processor is a central processing unit (CPU) that implements an instruction set where its instructions are designed to operate efficiently and effectively on large one-dimensional arrays of data called vectors.


Set of computer programs and associated documentation and data.

A diagram showing how the user interacts with application software on a typical desktop computer. The application software layer interfaces with the operating system, which in turn communicates with the hardware. The arrows indicate information flow.
Blender, a free software program

At the lowest programming level, executable code consists of machine language instructions supported by an individual processor—typically a central processing unit (CPU) or a graphics processing unit (GPU).


Communication between an information processing system, such as a computer, and the outside world, possibly a human or another information processing system.

Computer simulation, one of the main cross-computing methodologies.

In computer architecture, the combination of the CPU and main memory, to which the CPU can read or write directly using individual instructions, is considered the brain of a computer.

Multithreading (computer architecture)

A process with two threads of execution, running on a single processor.

In computer architecture, multithreading is the ability of a central processing unit (CPU) (or a single core in a multi-core processor) to provide multiple threads of execution concurrently, supported by the operating system.

Control unit

Animation of the control matrix of a simple hardwired control unit performing an LDA-instruction

The control unit (CU) is a component of a computer's central processing unit (CPU) that directs the operation of the processor.