A CPU, or central processing unit, is the primary component of a computer that executes instructions and performs calculations. It reads commands from memory, processes them, and writes results back to memory or storage. The CPU is responsible for arithmetic operations, logic decisions, and controlling the flow of programs. Every running process ultimately depends on CPU cycles to perform work. Modern CPUs contain multiple cores, allowing them to execute several instruction streams at once. Their performance is influenced by clock speed, cache sizes, and microarchitecture. CPUs interact closely with RAM, where they load instructions and data. They also rely on caches to reduce the cost of repeatedly accessing the same data. Even though GPUs and accelerators now handle specialized workloads, the CPU remains the general purpose workhorse of computing.
How it Works
A CPU follows a cycle of fetching an instruction, decoding it, executing the operation, and storing the result. It communicates with the system through buses that connect it to memory, storage, and peripherals. CPU instructions are defined by the processor's instruction set architecture, such as x86 or ARM. Operating systems schedule which processes get time on each CPU core and manage context switches between tasks. When a program uses too much CPU, it can slow down other applications or cause delays on a server. Understanding CPU behavior helps diagnose performance issues, especially when working with AI systems or high load applications.