Cheap Computer CPU
How it Works

Inner Basics

Part 1

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Your cheap computer CPU (Central Processing Unit) is the 'brain' that controls the internal activities of your computer.

Just like the human brain processes information and directs the body to perform certain actions, it processes instructions and directs the operations of the computer.

The CPU may also be called the Microprocessor or the Computer Processor

By whatever name it is called, it is the component that actually does the 'thinking'. All the other parts of the computer are designed around it.

The processor isn't just a very important component of the computer; it's crucial! Without one, the system couldn't perform. In other words, a computer system without a processor would be like a car without an engine -It simply wouldn't perform at all!

The reliability of your computer system is determined by the quality of your computer processor. The type of motherboard that you use would be determined by your choice of processor.

You can browse here for a wide range of cheap computer CPUs.
The microprocessor consists of three basic sections:

  1. The ALU (Arithmetic Logic Unit).
  2. Registers.
  3. Control Unit.

Internal Schematic of a CPU

Basic Internals of a CPU

Today's processors have more complex configurations but this is just caused by major modifications to the three basic sections. The outcome is an extremely efficient computer cpu.

These three sections of the microprocessor work together to control the operations of the system. They are connected to the system bus and handle the input, output and storage of data.

Let's examine the three sections of the microprocessor in more detail:

ALU (Arithmetic Logic Unit) - This unit performs the computing functions involving integers (whole numbers).

  • Arithmetic operations which include addition, subtraction, multiplication and division.
  • All logic operations which involve comparisons such as less than, greater than, or equal to.

All information in a processor is reduced to a numeric function; therefore, the ALU is constantly handling arithmetic and logic operations.

The results of these operations are stored in the registers or in memory or sent to output devices.

Registers - All data is temporarily stored in registers during the execution of programs and the size of the internal register determines how much information the CPU can process at one time.

Control Unit - This unit handles the timing and control signals to all the operations in the system. You can compare the control unit to a police officer directing traffic at a busy intersection; but, instead of directing cars, the control unit directs data flow between the computer processor, memory and peripherals.

This basically wraps up the functions of the three sections of the microprocessor.

You can check out my guide to installing the Computer Processor and Heat Sink/Fan Assembly here.

There are some other terms you will need to become familiar with before continuing, such as:

System Bus:
The processor transfers data to other components in the system through the system bus. There are two types of bus regularly referred to:

  • The Front-Side Bus (FSB) carries data between the processor and the Northbridge chipset.

  • The Back-Side Bus (BSB) connects the microprocessor to the cache.

The system bus or processor bus is an external data bus. External data bus describes the wires and traces on the motherboard that are used to send and receive data.

The greater the amount of traces (bandwidth), the more data you can send and receive. Bandwidth is referred to as the maximum theoretical throughput of the front side bus (FSB). In the first set of PCs, the bus was 8 bits wide, meaning that 8 bits could be transferred at the same time. (In the binary numbering system, a bit is a single digit, either a '1' or a '0'. A combination of 8 bits is called a byte).

Systems advanced and a faster rate of processing more data became necessary. As this need for faster processing of data increased, the bus width was expanded to 16 bits, then to 32 bits and then to 64 bits. A 64-bit bus can carry eight times as much data as an 8-bit bus. Today's systems utilize a 64-bit technology.

With advances in technology, processors capable of handling extremely large amounts of data are manufactured. Therefore, the buses had to be widened to facilitate the movement of huge amounts of data being processed hence the use of 64-bit technology.

A cache is a small amount of high speed memory provided to hold data. Some processors have cache which vary from 2MB to 12MB of static RAM (SRAM). Static ram performs much faster than dynamic RAM (DRAM) which is used for the system's main memory.

Present processors are equipped with L3 cache. Some examples of these are the Intel Core i7 and the AMD Phenom II X6 chips.

The data requested by the processor, is handled by the cache controller. The cache controller may be built into the processor or it may be built on the motherboard. Overall, cache dramatically increases the speed at which the computer processes data.

Because this cache is internal, it can be accessed directly and keeps up with the speed of the microprocessor. Without this cache, the microprocessor would have to wait for the data to come from the main memory.

In these present powerful chips, there are now billions of transistors. This is made possible because of the process technology used to miniaturize these internal components.

Processing has come from 90nm to 65nm to 45nm and now 32nm achieved by Intel.

Math Co-processor:
The Math co-processsor (also called the FPU or floating-point unit) handles decimal calculations. In computer language, these calculations are called floating-point math. These calculations slow down the processor but if a math coprocessor is present, it performs these operations much faster.

You have now learnt about the basic internal components of a computer processor. Let's go further and take a look at how it functions.

Click here to go to Part 2 of this Guide > > > >

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