central-processing-unit-CPU microchip

Functions, types, and components of processor (CPU)

The computer processor or Central Processing Unit (CPU) is termed the brain of the computer. It is the main component of any computing device that is available. It is usually made of microelectronic components fixed in a microchip.

The main function of the computer processor is to execute instructions and give the required output results. It is made up of 3 main components control unit (CU), Arithmetic Logic Unit (ALU), and the main memory (RAM). Processors can be classified in terms of the number of cores that they have into 6 types, Single, Dual, Quad, Hexa, Octa, and Deca-core.

4 Functions of computer processor (CPU)

  1. CPU fetches and executes commands.
  2. It temporarily stores data being processed and intermediate results.
  3. Controls all communication between RAM and all other input-output devices by interpreting data from and to the devices.
  4. It carries out all arithmetic calculations and performs logic operations.

Computer processor types

Before we discuss the types let’s first define what is a core. A processor core is a single command execution unit that can execute commands independently. A single CPU can have multiple cores which means it can execute many instructions simultaneously. This enables modern computing devices to have multitasking capabilities. 

To achieve even better CPU utilization processor manufacturers like Intel implement hyperthreading. Hyperthreading is creating two logical cores from one physical core. This allows assigning multithread to run in a single core for execution.

1. Single-core

This is the oldest type of processor from the time Intel started manufacturing the core type of processor. They have one CPU which has a single core. They are slow since they can only execute a single instruction at a time.

2. Dual-core

They are the second in line in the core processors. They have two cores within a single CPU. they are faster than single core and they can support multiprocessing. By use of hyperthreading, each core can have two logical cores which can make it four cores.

3. Quad-core

In this technology, a single CPU has four cores within it. This means that threads or instructions can be executed by all the cores at the same time. Again by use of hyperthreading, they can achieve an eight-logical core. They are high-performance computer processors that can be used in high-operation systems such as gaming computers.

4. Hexa-core

They are made of six cores within a single microprocessor. Hexacore is even more powerful than quad-core processors. They increase the level of multiprocessing to a very high level of operation. The processor has single quad-core and dual-core cores.

5. Octa-core

The CPU has 8 cores that offer even better multiprocessing capabilities. It comes with two sets of quad-core processors to achieve octa-core.

6. Deca-core

This offers ten independent core that is used to command execution. Of course, they offer more multiprocessing capabilities than all the other processors. It has two quad-core and a single dual-core which is a single CPU.

Summary of processor core types and examples.

Processor typeNumber of coreTypes of cores usedExamples of processors
Single-core11 coreIntel Celeron (B720), AMD-Embedded G-Series T40R 
Dual-core21 DualIntel Core Duo, Intel Pentium Dual Core, AMD X2
Quad-core41 QuadPowerPC G5, Intel Core 2 Quad, Intel Nehalem, AMD Phenom X4 
Hexa-core61Qaud, 1DualIntel Core i5-8650, AMD Ryzen 5 PRO 1600
Octa-core82QaudAMD Ryzen 7 4980U, Intel Core i7-9800X, Qualcomm Snapdragon 665
Deca-core102Qaud, 1DualIntel Core i9-9820X, MediaTek Helio X30 (MT6799), Cavium CN5745-1000 SSP

Central Processing Unit (CPU) components and functions

When most users define parts of a CPU they mention only 3 components ALU, CU, and RAM but when you drill down we can add even more components. Below we discuss 7 components that ensure the processor work effectively and efficiently.

components of a central processing unit (CPU) which includes, control unit (CU), ALU, Main memory (RAM), cache, and registers

1. Processor Control Unit (CU)

This is a unit that controls all activities that go on within the device. When processing instructions computer requires a mechanism to ensure activities are flowing the way they suppose and at the right time. The control unit of the processor ensures that is meant.

2. Arithmetic Logic Unit

ALU is where all calculation and logic operations happen. It is made up of arithmetic and logic units. The arithmetic unit deals with basic arithmetic operations such as addition, subtraction, multiplication, and division. The logic unit caters to logic operations such as AND, OR, NOT, and NOR.

3. Main memory (RAM)

RAM is counted as part of the CPU but it is not integrated within the microchip that carries the other component. It is part since the CPU cannot process data without having somewhere to store the data. Main memory (RAM) is used temporally to store data that is required for processing within the CPU.

4. Central Processing Unit registers

Registers are the very first temporally memories that are integrated within the processor. There are several registers that are used for different functions within the processor.

  1. A program counter (PC): stores the next instruction.
  2. Memory address register (MAR): stores the address of the next instruction.
  3. Memory data register (MDR): contains data that is to be read/written to or from the address.
  4. Current instruction register (IR): stores instructions being executed currently.
  5. Accumulator Register (AR): used to store intermediate results that are produced.

You can read more about the types of CPU registers and their functions in this other article.

5. Computer BUSes

These are pathways that data travels when the CPU is communicating with RAM and other input-output devices. There are 3 types of Computer Buses.

  • Address BUS: it carries the address of where data is going to and coming from in the RAM.
  • Control BUS: it carries control signal data that is used to control the communication between devices.
  • Data BUS: it carries the real data that is being transmitted from one location to another.

6. Cache memory

This is a memory type that is used to store data that is frequently used by the CPU. there are 2, primary and secondary caches. Primary is mostly intergraded within the processor while secondary cache can either be within or outside the processor. This memory increases the access speed of data since it is faster than the RAM. For more details about the types, functions, and characteristics of cache memory click on this article.

7. CPU clock

This is an electronic pulse that determines the number of cycles that a CPU executes instructions per second. The cycles are measured in Hertz. The current computer processors have a speed of Gigahertz (Billion cycles per second). The clock speed is given together with processor types and generation. Read more details on CPU/system clock types and their functions.

Factors affecting CPU speed

Determining CPU speed requires to use of many factors to avoid biased comparisons including generations. The most common factor that affects how fast a processor is are

  1. The number of cores: more cores means the process can be processed by many cores hence faster execution.
  2. Cache size: big cache means more data will be stored nearer to the processor hence high access speed. When access speed increases it means time wasted waiting for data from slower RAM is reduced.
  3. Clock speed: high clock speed lead to a faster processor. A 3GHZ processor will be faster than 2.3GHZ.
  4. Hyperthreading: it creates logical cores which means multithreading can be used to execute many threads at the same time.
  5. Instruction Set Architecture: this determines the number of location addresses that the processor can support. X86-64 processors will execute faster since they have a bigger memory location to store data when it is being executed.

NOTE: When comparing different processor speeds it is good to use more than one factor to get a better CPU for your purpose. 

How to check Intel core processor type and generation in Windows 10

For all computers using Intel core processors, they indicate the type and generation. generation is indicated by the number after the core number i3, i4, i5,i9, etc. For example Intel(R) Core(TM) i5-3320M means 3rd generation processor.

In the windows operating system, the computer clicks on system properties to view the type of processor in use.

Window describing how to check processor generation and CPU clock speed

You can read for more details on naming and numbers in the Intel core processor from the Intel website.

Types of computer processor socket type

There are 2 main categories of CPU sockets available for connection.

2 processor chip showing different sockets Pin Grid Array (PGA) and Land Grid Array (LGA)
  1. Pin Grid Array (PGA): in this type of socket the motherboard has the female connector. The CPU has pins that connect to the female part on the motherboard.
  2. Land Grid Array (LGA): The pins (male) are on the motherboard which connects to the female in the CPU.

Difference between X86 (32-bit) and X86-64 (64bit) processor architecture

These are architectures that determine the set of instructions that a given processor can work with. X86 architecture allows a maximum of 32bit of data(2^32)memory address while the theX86-64 has 64bit (2^64) memory. This limit the X86 system to 4GB of RAM while X86-64 has more than any computer may require today.

X86 (32-bit) system: It was used in the old computer’s processor and software development. It supports a maximum of 4GB of RAM address. 32bit software can only be used in the X86 system, with no upward compatibility.

X86-64 (64bit) system: most currency computers and smartphones use this architecture which can support more than 4GB of RAM addresses. Software today is designed to use 64bit processors which makes them fast and more efficient. 64bit system supports downward compatibility. 

This means 32bit software can run in a 64bit processor but 64bit software cannot run in a 32bit processor. Most types of operating systems are developed as 64bit operating systems to take advantage of X86-64bit architecture.

List of Central Processing Unit (CPU) manufacturers

The main processor competitors are Intel and ADM company which have been in the market for a long. The list below gives 5 main computer processor manufacturers in the world today.

  1. Intel
  2. AMD
  3. Apple
  4. Samsung 
  5. Huawei
  6. ARM Holdings MediaTek
  7. Qualcomm
  8. Cavium

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