A microprocessor is an electronic component that is used by a computer to do its work. It is a central processing unit on a single integrated circuit chip containing millions of very small components including transistors, resistors, and diodes that work together. Some microprocessors in the 20th century required several chips. Microprocessors help to do everything from controlling elevators to searching the Web. Everything a computer does is described by instructions of computer programs, and microprocessors carry out these instructions many millions of times a second. [1] Microprocessors were invented in the 1970s for use in embedded systems. The majority are still used that way, in such things as mobile phones, cars, military weapons, and home appliances. Some microprocessors are microcontrollers, so small and inexpensive that they are used to control very simple products like flashlights and greeting cards that play music when you open them. A few especially powerful microprocessors are used in personal computers.

1. Pentium II processor
 Bus speeds : 66 MHz; 100 MHz
 CPU clock multiplier: 3.5x, 4x, 4.5x, 5x
 CPU Speeds : 233 MHz, 266 MHz,300 MHz,333 MHz, 350 MHz, 400 MHz, 450
MHz
 Cache memory : 16K x 2( 32KB) L1,512KB – ½ speed L2
 Internal registers: 32 bit
 External data bus: 64 bit system bus
 Memory address bus : 36 bit
 Addressable memory : 64 GB
 Virtual memory : 64 TB
 Power management: SMM
Pentium III processor
 The first Pentium III core, featured SSE instruction set, which allowed SSE-enabled
applications to process up to four single-precision floating point numbers at once.
 Other Pentium 3 cores added other features, like 256 and 512 KB on-die L2 cache
memory and smaller package size.
 During its lifetime, the core of Pentium III microprocessors was shrunk twice - from
0.25 micron to 0.18 micron, and then to 0.13 micron.
Pentium IV Processor
 Speeds range from 1.3 GHz – 3.8 GHz
 FSB speed : 400 MHz, 533 MHz, 800 MHZ, 1066 MHz
 Hyper pipelined/ hyper threading technology
 L2 cache can handle upto 4GB RAM
 Bus width is 64 bits