Instead of a mouse, laptops may have a touchpad or pointing stick. The monitor in the folding upper cover of the case can be closed for transportation, to protect the screen and keyboard. Laptops contain the keyboard, display, and processor in one case. They may use lower-power or reduced size components, with lower performance than a similarly priced desktop computer. Laptops are designed for portability but operate similarly to desktop PCs. Separating the elements allows the user to arrange the components in a pleasing, comfortable array, at the cost of managing power and data cables between them.

Some models of desktop computers integrated the monitor and keyboard into the same case as the processor and power supply. The computer case holds the motherboard, fixed or removable disk drives for data storage, the power supply, and may contain other peripheral devices such as modems or network interfaces. Desktop personal computers have a monitor, a keyboard, a mouse, and a computer case. The personal computer is one of the most common types of computer due to its versatility and relatively low price. Types of computer systems Personal computer Basic hardware components of a personal computer, including a monitor, a motherboard, a CPU, a RAM, two expansion cards, a power supply, an optical disc drive, a hard disk drive, a keyboard and a mouse Inside a custom-built computer: power supply at the bottom has its own cooling fan This is referred to as the Von Neumann bottleneck and often limits the performance of the system. The meaning of the term has evolved to mean a stored-program computer in which an instruction fetch and a data operation cannot occur at the same time because they share a common bus. This describes a design architecture for an electronic digital computer with subdivisions of a processing unit consisting of an arithmetic logic unit and processor registers, a control unit containing an instruction register and program counter, a memory to store both data and instructions, external mass storage, and input and output mechanisms. The template for all modern computers is the Von Neumann architecture, detailed in a 1945 paper by Hungarian mathematician John von Neumann.

Main articles: Von Neumann architecture and Stored-program computer Von Neumann architecture scheme

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