The CPU, or central processing unit, is the microprocessor at the heart of a computer, connected directly to the motherboard. It determines how quickly the computer can process data and execute tasks, with speed measured in megahertz (MHz) or gigahertz (GHz). A faster CPU is essential for digital imaging and photography workflows, as it reduces processing time for tasks such as image editing, rendering, and batch processing. Modern CPUs often feature multiple cores and advanced architectures to handle complex photographic software efficiently.