A microprocessor chip-- also known as a central processing unit (CPU) -- is a complete computation engine of computers, embedded systems or other electronic devices. A chip is also called an integrated circuit, which can contain millions of transistors.
A microprocessor executes a collection of machine instructions that tell the processor what to do. Based on the instructions, a microprocessor does three basic things:
- Performs mathematical operations and modern microprocessors contain complete floating point processors that can perform extremely sophisticated operations on large floating point numbers.
- Moves data from one memory location to another.
- Makes decisions and jump to a new set of instructions based on those decisions.
More important than knowing how a microprocessor works is knowing about a microprocessor's power and speed.
The Microprocessor's Power
The power of a microprocessor is measured in bits. The more bits, the more information (data) the microprocessor is capable of bandying about and, therefore, the more powerful the microprocessor. Specifically, an 8-bit CPU can add/subtract/multiply/etc. two 8-bit numbers, while a 32-bit ALU can manipulate 32-bit numbers. An 8-bit arithmetic logic unit (ALU) would have to execute four instructions to add two 32-bit numbers, while a 32-bit ALU can do it in one instruction.
In a way, the number of bits can be compared to lanes on a freeway: If you have only two lanes, too many cars congest traffic, and things slow down. A six-lane freeway, however, has plenty of room for lots of cars, and traffic flows smoothly. With more bits, just as with more lanes on a freeway, the microprocessor can do more powerful programming, operations and processes.
Technically, microprocessor speed is measured in hertz, or cycles per second. Microprocessors are capable of doing billions of things in one second. Therefore, their speed is measured in gigahertz (GHz). A microprocessor that can do 1 billion things per second is rated at 1.0 GHz. A microprocessor that can do 3.66 billion things per second is rated at 3.66 GHz. This rate is much faster than 1.0 GHz. The higher the speed value, the faster the chip. And, naturally, the faster the chip, the more you can do in a given amount of time.