Information and Pictures
On larger machines, CPUs require one or more printed circuit boards, whereas on personal computers or small workstations, the CPU is enclosed in a single silicon chip called a microprocessor. After the 1970s, the microprocessor style CPUs completely overtook all of the other types or implementations of CPU. Current CPUs are integrated circuits on a large scale housed in packages that are often less than 4cm square, with hundreds of connecting pins.
Intel 80486DX2 CPU (above)
An Intel 80486DX2 CPU from above.
A cool angled picture of a CPU.
Intel 80486DX2 CPU (below)
An Intel 80486DX2 CPU from below.
What The CPU Does
The CPU is the central unit of the motherboard. All hardware components and programs installed on the computer system, must go through the CPU before their function can be carried out. When a function, program or piece of data is called, the CPU pulls it from RAM (or Random Access Memory) and any other hardware that's required to process it. The CPU reads the instructions for the task and then sends it back to RAM. The system bus is the route the data must travel before it is executed. It is the CPU's job to make sure the data is guided through the system bus to be processed by CPU and then move on to the next step. On each stop on route, the CPU checks that the data arrives in the correct order.