Difference Between the CPU & Motherboard
The inside of your computer's case contains components that each perform specific roles. The motherboard is a large, flat piece of silicon, while the CPU (Central Processing Unit) is a chip installed on the motherboard.
In addition to the CPU, the motherboard has slots for RAM (Random Access Memory) installed in "sticks." RAM is used temporarily for rapid storage and retrieval of data. You may also be able to install video display, computer network, and audio devices.
The CPU is the "brain" of your computer. Popular manufacturers are Intel and AMD (Advanced Micro Devices). The CPU typically has a large heatsink and fan on it, distinguishing it from other components in the case.
Heatsinks and Fans
Heatsinks are finned blocks of metal, usually aluminum or copper, use to remove heat from the CPU more quickly. An attached fan then blows this heat away from the heatsink.
A motherboard contains copper "traces," which are thin threads of metal that the board uses to transmit information and electricity. These traces are printed onto the board and create circuits, hence "printed circuit board," or PCB.
A CPU, meanwhile, is created in a fabrication plant (a "fab") on wafers. These wafers are sheets of CPUs. A CPU also contains millions, sometimes billions, of transistors that are used to perform millions of instructions per second that are sent through the copper traces on the motherboard.