Centralbearbetningsenhet

Centralbearbetningsenhet (CPU) is the central component of a computer responsible for executing programs and coordinating the work of other hardware. It retrieves program instructions from main memory, decodes them, and performs the required operations, writing results back to memory or I/O devices. A modern CPU typically includes a control unit, one or more arithmetic logic units (ALUs), multiple registers, and cache memory. Some CPUs also contain a floating point unit (FPU) and specialized accelerators for graphics or cryptography.

Through an underlying instruction set architecture (ISA) such as x86, ARM, MIPS, or RISC-V, the CPU defines which operations are available and how they are encoded. Microarchitectural features—pipelining, superscalar execution, out-of-order execution, speculative execution, and caches—determine how quickly instructions are processed. Multicore designs enable parallel instruction streams, while simultaneous multithreading can improve utilization of execution resources.

CPU evolution began with early mechanical and vacuum-tube devices, progressing to integrated circuits in microprocessors during the 1970s. Over time, CPUs have grown in core count, clock speed, and cache hierarchy, while emphasis has shifted toward energy efficiency, performance-per-watt, and support for diverse ISAs and software ecosystems. Modern CPUs also integrate multiple dies or chiplets and employ advanced packaging technologies.

In use, the CPU is complemented by memory hierarchies, input/output subsystems, and a system bus. It powers desktops, servers, mobile devices, and embedded systems, with variations such as microcontrollers for simple tasks and application processors for complex workloads. The CPU remains a focal point of computer architecture, shaping performance, design, and software compatibility.