CPUs

A central processing unit (CPU) is the primary component of a computer that executes instructions. It fetches, decodes, and executes program commands, performs arithmetic and logic operations, and moves data between memory and I/O. A typical CPU includes a control unit, an arithmetic-logic unit (ALU), and registers, with a memory hierarchy and caches on the same chip to speed data access.

CPUs operate according to an instruction set architecture (ISA), which defines supported operations and data formats. Common ISAs include x86, ARM, and RISC-V. Modern CPUs use techniques such as pipelines, superscalar execution, and sometimes out-of-order and speculative execution, aided by branch prediction and cache hierarchies. Many designs integrate memory controllers and security features, and support multithreading.

Most contemporary CPUs are multicore, with several processing cores on a single package. Each core executes instructions independently while sharing caches and interconnects. Performance depends on clock speed, instructions per cycle, core count, cache size, memory bandwidth, and power consumption. Efficiency and thermal design play major roles in mobile and data-center CPUs.

CPUs have evolved from early microprocessors to support complex operating systems and virtualization. They are manufactured using shrinking semiconductor nodes and increasingly integrate multiple components on a single chip. In many systems, CPUs coexist with specialized accelerators such as GPUs and NPUs, but remain the general-purpose computing backbone of most devices.