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The processor is also known as the ‘Central Processing Unit’ (CPU). It is the heart, soul and the brain of the computer. It is the most important component on the system’s motherboard. The integrated circuits of the processors are etched on silicon chips and the process is called photolithography that is accomplished with the ultraviolet light. The limiting factor is the wavelength of the light. The processor computes and processes data and delivers the results based on the instructions by synchronising between the transistors. Scientists have managed to squeeze millions of transistors onto each chip. Each transistor on the surface of a silicon chip acts as a switch that can open or close a gate. Computer processes information by manipulating sequences of opened and closed gates. A positive charge applied to the gate attracts electrons, allowing current to flow across the gap from the source to the drain. A negative charge stops the current and closes the gate. Higher the number of transistors on a processor the more data will process in a given unit of time. Older processors had a distance of one micron between the transistors. The transistor density in vogue now is 0.18 micron. The processor’s architecture determines the manner in which it processes data. New processors employ multistage pipelines for transmitting data. To ensure proper data flow through these pipelines, the processor includes a kind of prediction and error correction mechanism. The clock speed is the speed at which the processor executes instructions. The clock speed is measured in megahertz (MHz), which stands for a million instructions per second. The MHz rating is considered the most important measure of processor performance. Higher clock speeds mean faster processors. The system Bus transports the data needed by the processor. The system Bus comes on a number of speeds ranging from 66 MHz to 200 MHz in modern processors. Another important consideration is Bus width. The processor will be faster if it has a fast and wide bus. Floating point math decides how 3D games, flight simulators, 3D rendering software, designing software etc., work. Floating decimals take more power to crunch but a more floating-point math capable processor delivers better performance. Processors produce a lot of heat and some high-end processors require super cooled gases to maintain the temperature. Processor heat can be managed by designing processors that consume less power. If the processor is not cooled properly, then it might lead to all sorts of errors, including system crashes. Therefore, a heat sink or a small cooling fan to dissipate the heat usually covers the processor. The average number of instructions a processor can execute in a second is called MIPS. The Higher MIPS rating means better performance. The functioning of a processor is quite technical in nature. But very briefly, a processor works by taking program code and data from the ‘System Memory’ (RAM), executing the code and returning the results to the RAM. Logically, a processor is divided into two main parts, the ‘Arithmetic Logic Unit’ (ALU) and the ‘Control Unit’. The ALU performs all the arithmetic and logical operations on the data. The control unit acts as an intermediary between the ALU and the RAM. The control unit controls the functioning of the processor. It accepts the data from the RAM. Passes the data to the ALU for performing arithmetic and logical operations, and returns the processed data back to the RAM. ‘Multimedia Extensions’ (MMX) is a set of instructions built into the processor, specifically intended for improving the performance of multimedia or graphics applications, mainly games. However, computers need to have applications specifically designed to take advantage of MMX. In general terms, a processor is a complete computation unit that is fabricated in a single chip to do all the computation and logic processing. The history of the microprocessor goes way back to the year 1971 when the Intel 4004 microprocessor was launched. A microprocessor is a collection of machines that work in a synchronous manner. There are many logic circuits that are present inside a microprocessor which work together to produce results. Since computers are digital devices they deal only with zeros and ones. The building blocks of a microprocessor is the logic gates like ‘and’, ‘or’, ‘not’ gates. There are digital switches that take inputs and produce outputs according to the formula and logic applied. Initially, the processors used to have electro-mechanical switches that were slow and used to consume enormous amounts of power. But with the invention of transistors the whole computing scene changed. A transistor can be considered a digital switch. Not only does it consume less power, there are no moving parts. In modern processors, transistors are fabricated in to a single chip to form an integrated circuit. They are connected internally and do not require any writing to be done. Special materials are used to form these integrated circuits called semi-conductors like silicon, germanium, etc. Once the integrated circuits were invented than everybody realized an integrated circuit is made more miniature, the more powerful it will be. Initially, the processor used to have large-scale integration that used to pack hundreds of transistors together. But soon the integration went in to very large-scale where millions of transistors were packed in a single integrated circuit. Originally, the functions performed by a processor were implemented using several different logic chips. Intel was the first company to incorporate all these logic components into a single chip. One important aspect, which differentiates between processor and hardwired logic, is that the processors were programmable. They can perform different functions based on the instructions from different software. With the help of different sets of pre-configured subtask or instruction it enables users to write programs to use these task. The inside of processor consists of logic circuits like ‘Arithmetic Logic Unit’ (ALU). Its function is to perform mathematical operations like addition, subtractions, divisions, etc. Modern microprocessors contain complete floating-point processors that can perform extremely sophisticated operations and applications no large floating-point numbers. Also present is an address bus that may be 16 bits or 32 bits wide and is used to send addresses to the memory. It includes a data bus that is used to send and receive data from memory is again 16 bits or 32 bits wide. A clock line lets a clock pulse, which sequences the processor, and a read and a write line tells the memory weather to read or write data in memory. A reset line sets the program counters to zero. The number of transistor available affects the performance of processor. A typical instruction in a processor like an 8088 takes about 15 clock cycles to execute. More transistors also make possible a technology called pipelining. In a pipelined architecture, instruction execution overlaps and so even though it might take five clock cycles to executes each instruction, there can be five instruction in various stage of execution simultaneously. That way it looks like one instruction completes every clock cycle, so much for microprocessor efficiency.