A single-core processor is a microprocessor with a single CPU on its die.[1] It performs the fetch-decode-execute cycle one at a time, as it only runs on one thread. A computer using a single core CPU is generally slower than a multi-core system.
Single core processors used to be widespread in desktop computers, but as applications demanded more processing power, the slower speed of single core systems became a detriment to performance. Windows supported single-core processors up until the release of Windows 11, where a dual-core processor is required.[2]
Single core processors are still in use in some niche circumstances. Some older legacy systems like those running antiquated operating systems (e.g. Windows 98) cannot gain any benefit from multi-core processors. Single core processors are also used in hobbyist computers like the Raspberry Pi and Single-board microcontrollers. The production of single-core desktop processors ended in 2013 with the Celeron G440, G460, G465 & G470.[3]