What is the CPU? Why is the CPU most important component in a computer

By / December 24, 2020
Why is the CPU the most important component in a computer

What is the central processing unit on a computer?

Processor (microprocessor, CPU, central processing unit, unlocked – stone, percent, etc.) – one might say that the heart of the computer, the brain, is the central part. It processes information, executes all user commands, and controls the rest of the system unit devices. The power of the processor determines how fast the computer programs will work. It’s a part of a computer.

The processor is mounted on the motherboard and placed in a special socket called a CPU socket. There are many sockets; in each of them, you can install only a specific type of “stone.” CPU must do the installation in the socket of the motherboard CPU very carefully. A little carelessness on your hand can damage the pins in the CUP’s socket.

What is CPU in computer? How is it working process?

Type of CPU

  • Single-core
  • Dual-core
  • Quad-core
  • Hexa core
  • Octa-core
  • Deca core processor

Working principle of CPU

Von Neumann’s architecture is the foundation of modern computers. Under this computer architecture, programs and data are stored in a unified manner; instructions and data need to be accessed from the same storage space, transmitted via the same bus, and cannot be executed overlapping. According to the Von Neumann system, the CPU work is divided into the following five stages: instruction fetching stage, instruction decoding stage, instruction execution stage, access number, and result write back.

  • Instruction fetch (IF, instruction fetch) is fetching instructions from the instruction register’s main memory. The program counter’s value is used to indicate the current instruction’s position in the main memory. When an instruction is fetched, the PC’s value will automatically increase according to the instruction word’s length.
  • In the instruction decode stage (ID, instruction decode), after fetching the instruction, the instruction decoder splits and interprets the retrieved instruction according to the predetermined instruction format and distinguishes different instruction categories and various types of operands method.
  • The execution instruction stage (EX, execute) specifically realizes the function of the instruction. The different parts of the CPU are connected to perform the required operations.
  • In the access stage (MEM, memory), the main memory is accessed, and the operand is read according to the instruction needs. The CPU obtains the operand’s address in the main memory and reads the operand from the main memory for operation. Some instructions do not need to access the main memory. You can skip this stage.
  • The result writes backstage (WB, write back), as the last stage, the result writes backstage “writes back” the operation result data of the execution instruction stage to some storage form. The resulting data is generally written to the internal registers of the CPU so that subsequent instructions can quickly access it; many instructions will also change the state of the flag bits in the program status word register. These flag bits indicate different operation results and can be Used to influence the actions of the program.
  • After the instruction is executed and the result data is written back, if no unexpected events (such as result overflow, etc.) occur, the computer will obtain the next instruction address from the program counter and start a new cycle. The next instruction cycle will be taken out sequentially One instruction.

What is CPU performance?

The main indicators that affect its performance are the main frequency, the number of bits of the CPU, and the CPU’s cache instruction set. The so-called main frequency of the CPU refers to the clock frequency, which directly determines the CPU’s performance. Therefore, if the performance of the CPU is to be improved, it is a good way to increase the main frequency of the CPU. The number of CPU digits refers to the number of floating-point numbers that the processor can calculate at one time. Generally, the higher the number of CPU digits, the faster the CPU performs operations.

Now the number of CPU bits is generally 32 or 64 bits. In the past, computers used by people were 32-bit systems. In recent years, the proportion of 64-bit processors in the computers used by people has become more. This is because 64-bit computers have become faster and have improved people’s Work efficiency. The CPU’s cache instruction set is stored inside the CPU, which mainly refers to the hard program that can guide and optimize the CPU operation. Generally speaking, the cache of a CPU can be divided into a first-level cache, a second-level cache, and a third-level cache. Those processors with stronger processing capabilities generally have a larger third-level cache.

What is the structure of the CPU

CPU structure

Generally speaking, the structure of a CPU can be roughly divided into arithmetic logic components, register components, and control components. The so-called arithmetic logic components are mainly capable of performing related logic operations, such as shift operations and logic operations, fixed-point or floating-point arithmetic operations, and address operations and conversion commands, functional arithmetic unit.

The register component is used to store instructions, data, and addresses temporarily. The control component is mainly used to analyze the instruction and can send out the corresponding control signal. The computer memory can be divided into random access memory ( RAM ) and read-only memory ( ROM ). The difference between the two is that the random access memory can directly exchange data with the CPU, and it can also be called the main memory.

The RAM can be read and written at any time. The speed of this process is super fast, so due to this advantage of the main memory, it is often used as a temporary data storage medium for the operating system or other running programs; and the read-only memory ROM is a kind of memory that can only read the data stored in advance. The user does not have any right to change the data stored in it and cannot delete it, and the data will not disappear after the power is turned off. This kind of memory has also been widely used and is well used in electronic or computer systems where data does not need to be changed frequently.

The central processing unit can be regarded as a large-scale integrated circuit whose main task is to process various data. The traditional computer’s storage capacity is relatively small, it has a certain difficulty in the process of large-scale data processing, and the processing effect is relatively low. With the rapid development of my country’s information technology level, a high-configuration processor computer has emerged. The high-configuration processor is used as the control center, which plays an important role in improving the computer’s CPU structure and function. The central processing unit’s core part is the controller and arithmetic unit, which play an important role in improving the computer’s overall function. It can realize the proliferation of multiple functions such as register control, logic operation, signal transmission, and reception and lay a good foundation for improving the computer basis’s performance.

The integrated circuit plays the role of regulating signals in the computer and executes different command tasks according to the user’s operating instructions. The central processing unit is a very large-scale integrated circuit. It is composed of arithmetic units, controllers, registers, etc., as shown in the figure below. The key operation is the processing and processing of various data.

Traditional computers have a small storage capacity and low operating efficiency for large-scale data sets. The new generation of computers uses high-configuration processors as the control center, and the CPU has a lot of opportunities for development in terms of structure and function. The central processing unit uses arithmetic units and controllers as the main devices. It gradually spreads into multiple functions such as logic operations, register control, program coding, and signal transmission and reception. These all speed up the optimization and upgrading of CPU control performance.

CPU bus

The CPU bus is the fastest in a computer system, and it is also the core of the chipset and motherboard. People usually call the local bus directly connected to the CPU CPU bus or internal bus and call those local buses connected to various general-purpose expansion slots as a system bus or external bus. In a CPU with a relatively single internal structure, there is often only a set of data transfer buses, the CPU internal bus, which is used to connect the CPU’s internal registers and arithmetic logic operation components. Therefore, this type of bus can also be called. It is the ALU bus. The bus inside a component connects the chips by using a set of buses, so it can be called an intra-component bus, which generally includes two sets of lines, an address line and a data line. The system bus refers to the line that connects the various components inside the system and is the basis for connecting the whole system; the bus outside the system is the basic line that connects the computer and other devices.

What are the three components of the CPU?

1. The arithmetic unit

The arithmetic unit refers to a computer that performs various arithmetic and logical operations. The arithmetic and logic unit is a part of the central processing core.

Arithmetic logic unit – ALU

An arithmetic logic unit refers to a combinational logic circuit that can realize multiple arithmetic operations and logic operations. It is an important part of central processing. The arithmetic logic unit’s operation is mainly to carry out two-bit arithmetic operations, such as addition, subtraction, and multiplication. The arithmetic logic unit mainly performs arithmetic and logic operations in centralized computer instruction in the calculation process. Generally speaking, ALU can play direct reading and reading, specifically reflected in the processor controller, memory, and input and output devices. , Input and output are implemented based on the bus. The input instruction contains an instruction word, including operation code, format code, etc.

Intermediate register – IR

Its length is 128 bits, and the operand determines its actual length. IR plays an important role in the “push into the stack and fetches” instruction. During the execution of this instruction, the contents of ACC are sent to IR, and then the operand is fetched to ACC, and then the contents of IR are pushed into the stack.

Operation accumulator – ACC

Current registers are generally single accumulators with a length of 128 bits. For ACC, it can be regarded as a variable-length accumulator. In narrating instructions, the expression of ACC length is generally based on ACS’s value, and the ACS length is directly related to the ACC length. The doubling or halving of the ACS length can also be regarded as doubling or halving the ACC length.

Description word register – DR

It is mainly used in storing and modifying description words. The length of DR is 64 bits. To simplify data structure processing, the use of description words plays an important role.

B register

It performs an important role in the adjustment of instructions. The B register’s length is 32 bits, and the address modification amount can be saved in modifying the address. The main memory address can only be modified with a descriptive word. Pointing to the first element in the array is the description word, so access to other elements in the array should require a modifier. For number, the composition is composed of data of the same size or elements of the same size and is stored continuously. The common access method is the vector description word. Because the address in the vector description word is byte address, In the conversion process, the basic address should be added first. For the conversion work, it is mainly realized automatically by hardware.

2. The control unit

The controller connects to the control device that changes the wiring of the main circuit or the control circuit and changes the resistance value in the circuit according to a predetermined sequence to control the start, speed, brake, and reverse of the motor. The controller comprises the program status register PSR, the system status register SSR, the program counter PC, and the instruction equalizer. As a “decision-making body,” the main task is to issue commands and play the role of coordination and control of the whole computer system operation. The classification of control mainly includes two kinds, namely the combinational logic controller and micro-program controller. Both parts have their own advantages and disadvantages. Among them, the combinational logic controller structure is relatively complex, but the advantage is that it is faster; the microprogram controller structure is simple, but in the modification of a machine instruction function, all the microprograms need to be reprogrammed.

3. Memory structure

The main function of the memory is to store programs and data. Programs are the basis for computer operations, and data are objects of computer operations. The memory is composed of a memory bank, address decoder, read-write control circuit, address bus, and data bus. The memory that can directly and randomly access instructions and data by the central processing unit is called the main memory. The large-capacity memory, such as magnetic disks, tapes, and optical disks, are called external memory (or auxiliary memory). The computer’s storage system is composed of main memory, external memory, and corresponding software.

The main control technology of CPU

The powerful data processing function of the central processing unit has effectively improved the computer’s work efficiency. In the data processing operation, it is not just a simple operation. The central processing unit’s operation is based on the instructions and tasks issued by computer users. In executing the instruction task, the user’s control instruction input corresponds to that of the CPU. With the rapid development of information technology in our country, computers have been widely used in people’s lives, work, and corporate office automation. As the main control device, they promote the development of e-commerce networks and upgrade CPU control performance. The process has been greatly improved. Command control, actual control, operation control, etc., are computer CPU technology applications’ performance.

  1. Select-control: The centralized processing model’s operation is implemented based on specific program instructions to meet computer users’ needs. The CPU can choose according to the actual situation to meet the user’s data flow requirements. The important role played by command and control technology. According to users’ needs, the calculation method is formulated to maintain the orderly formulation of data command actions. During the execution of the CPU, the implementation of the instructions of the program is completed smoothly. Only by following a certain sequence can the computer use effect be guaranteed. The CPU is mainly used to expand the automatic processing of data sets, which is the key to realize centralized control, and its core is instruction control operation.
  2. Insert control: The generation of the operation control signal by the CPU is mainly realized through instructions. The purpose of controlling these components is achieved by sending instructions to the corresponding components. The realization of an instruction function is mainly accomplished by a sequence of operations performed by computer components. More small control elements are the key to building a centralized processing model. The purpose is to complete the CPU data processing operations better.
  3. Time control: Applying time timing to various operations is the so-called time control. When an instruction is executed, it should be completed within the specified time. The CPU instruction is fetched from the cache or memory, and then the instruction decoding operation is performed, which is mainly implemented in the instruction register. In this process, Pay attention to control the program time strictly.

Evaluation of processor capabilities (Features)

Number of Cores

A modern processor has multiple cores. In solutions for consumer computers, their number varies from 2 to 32. A multi-core processor divides the load between several “data centers,” so the computer’s performance increases. It solves several problems simultaneously and does not slow down, does not freeze when faced with a challenging task.

But that’s in theory. In practice, everything is somewhat more complicated. Much depends on the CPU clock speed, its architecture, and whether you use software that supports multithreading. Therefore, in reality, a dual-core processor can demonstrate better results than a quad-core one.

The best way to choose the core of the CPU

  • 2 Cores: For solving simple tasks at home and in the office: you can work with texts, tables, and presentations, go online, watch videos, and listen to music, use databases.
  • 4-6 Cores: For solving resource-intensive tasks, including games, and for working with graphics at a professional level.
  • 8 or more cores: To create the most powerful gaming PCs and solve complex work tasks related to video and audio processing.

Clock frequency

In simpler terms, clock speed is the number of operations a processor can perform per second. The higher this number, the more productive the processor will be. However, performance depends on some other parameters, including the architecture and the size of the first, second, and third-level cache. By this parameter, all processors can be divided into several groups:

  • Up to 3 GHz: Budget processors are designed to work with office programs and other simple tasks.
  • 3 to 4 GHz: One-stop solutions for work, play, and play.
  • More than 4 GHz: CPUs are designed to solve complex problems and run resource-intensive games and professional programs.

Today, there are processors on sale, the performance of which can be increased. These are models with an open or unlocked multiplier. The process of increasing performance is called overclocking or overclocking. Depending on the specific CPU, it can be done through the BIOS or in an application used to adjust computer settings. It should be borne in mind that overclocking increases performance and power consumption, leading to overheating.

Cache memory

The cache (or cache memory) allows you to reduce the average access time to computer memory and increase the processor’s speed. In modern CPUs it is usually multilevel.

The higher the cache level, the larger its size, but the speed decreases. The L1 cache is especially quick to respond to a processor request, but it is inferior in size to L2 and L3.

Major CPU manufacturers

Currently, for many years, the market has been dominated and competed by two processor companies. These companies are called Intel and AMD. There are other manufacturers, but their market share is too small. Intel and AMD are in a constant battle for leadership in the manufacture of increasingly powerful and efficient modern computers CPU. This rivalry is an essential factor that favorably affects the industry’s development and reduces devices’ cost.

The processor is a semiconductor silicon crystal grown under special conditions and using a unique technology. Outwardly, it looks like a small board (about 5×5 cm in size) with many contacts on one side and a metal cover on the other.

Inside is a very complex structure that includes hundreds of millions of transistors. They process data and perform arithmetic calculations, which are based on mathematical operations with numbers. It is in them that the transformation of all incoming information takes place.

Thus, the processor consists of cells that process information, which is called registers. They analyze and process all data, i.e., the CPU reads the instructions’ sequence in the records and executes them. This sequence of commands is called a development program.

Intel

According to the Intel product line plan, there are currently three Intel nine-generation Core products: i9/i7/i5. In addition to high-cost performance, Intel’s nine-generation Core can also make laptops more portable, better wireless network connection capabilities, Faster data transfer speed. In terms of products, Intel’s 9th-generation Core H series and HK series are based on the Coffee Lake architecture of 14nm process technology, including Intel Core i5-9300H, Intel Core i5-9400H, Intel Core i7-9750H, Intel Core i7-9850H, Intel Core i9-9880H, and Intel Core i9-9980HK, among which the ninth-generation Core H series processors are generally used in gaming notebooks. The ninth-generation Core i5 core graphics card is UHD630 and supports dual-channel DDR4-2666 memory. In addition to the increase in CPU frequency and threads, the new platform can use the improved Intel Dynamic Tuning to maximize the performance of the processor; use Intel Thermal Velocity Boost technology to increase further the frequency based on turbo; at the same time, it also optimizes the bottom layer for the new graphics card. Enhanced the support of Thunderbolt 3 interface.

AMD

AMD Athlon X4 860K is a quad-core processor launched by AMD for the entry-level market to replace the previously released 760K. The Athlon X4 860K adopts the Kaveri architecture and adopts a modular design. The two cores share a floating-point computing unit, which is the same as the A10 APU. We can regard it as the A10 without GPU. This processor uses a native quad-core design with a 4MB L2 cache. The default frequency is 3.7GHz, which can be dynamically adjusted to 4.0GHz under high load.

Classification of computer CPU

Instruction set

According to the instruction set, the CPU classification can also be divided into reduced instruction set computer (RISC) and complex instruction set computer (CISC). RISC is a chip designed based on integrated circuits. Still, the difference is that it has improved the number of instructions and the addressing method, making it easier to implement. The degree of parallel execution of instructions is better, and the compiler efficiency has also become higher and higher. However, because the early integration technology was not developed enough, the early computers were often CISC architectures, requiring fewer machine languages ​​to complete the required computing tasks. As people’s needs increase, more relatively complex instructions are added to the instruction system, making the computer programs more intelligent. At the same time, it highly improves the processing efficiency of the information processing system. This is also RISC. The reason for formation.

Embedded system CPU

The scope of the traditional embedded field is extensive, and it is the main application field of the processor and the server and PC fields. The so-called “embedded” means that in many chips, the processor contained in it is as if it is embedded in it and is unknown.

With the further development of various new technologies and new fields, the embedded field has also been developed into several different sub-fields and differentiated.

First of all, with the development of smartphones (Mobile Smart Phone) and handheld devices (Mobile Devices), the mobile field has gradually developed into an independent field that rivals or even exceeds the PC field in scale. Because the Mobile field processor needs to load the Linux operating system and involve a complex software ecosystem, it has the same serious dependence on the PC field’s software ecosystem.

Followed by the real-time (Real-Time) embedded field. Relatively speaking, this field does not have such serious software dependence, so there is no absolute monopoly. However, due to the successful commercial promotion of ARM processor IP, ARM’s processor architecture still accounts for most of the market share. Other processor architectures, such as Synopsys ARC, etc., also have good market results.

Finally, there is a deeply embedded field. This field is more like the traditional embedded field mentioned earlier. The demand in this field is huge, but it focuses on low power consumption, low cost, and high energy efficiency. There is no need to load a large application operating system like Linux. Most of the software requires customized bare-metal programs or simple real-time operating systems. Therefore, The dependence on software ecology is relatively low.

Mainframe CPU

Mainframe, or mainframe. Mainframes use dedicated processor instruction sets, operating systems, and application software. The term mainframe originally referred to a large computer system housed in a huge iron box with a frame to distinguish it from smaller minicomputers and microcomputers.

Reducing mainframe CPU consumption is an important task. Saving each CPU cycle can delay hardware upgrades and reduce software licensing fees based on the scale of use.

The mainframe architecture mainly includes the following two points: a high degree of virtualization and shared system resources. Mainframes can integrate a large number of loads into one and maximize resource utilization, asynchronous I/O operations. That is, when the I/O operation is performed, the CPU hands the I/O instructions to the I/O subsystem for completion, and the CPU itself is released to execute other instructions. Therefore, the host computer can perform other tasks at the same time while performing heavy I/O tasks.

CPU overheating protection

While the computer is running (especially in modern games or when running resource-intensive programs), the processor gets very hot. For it not to fail due to banal overheating, a cooling system is attached to it. It consists of a heatsink and a fan (cooler) to dissipate heat.

The upper part of the processor is designed as a metal cover designed to dissipate heat. For maximum heat dissipation, the cooling system’s heatsink should fit the CPU as tightly as possible. It’s achieved by using thermal paste – a particular paste with high thermal conductivity. Without an excellent cooling system, the processor will heat up quickly.

Modern processors computers have superior overheating protection. When a critical temperature is reached, the computer turns off, and until the processor cools down, it will not be possible to turn it on again. The cooling system can be ineffective if the cooler is clogged with dust. Therefore it is recommended to clean the system unit from dust and dirt every 2-3 months.

What are hybrid processors?

Hybrid solutions are worth mentioning separately. They combine the central processor with the graphics. This helps to reduce power consumption and lower system costs. Based on hybrid processors, you can create compact computers that do not need to solve complex problems.

Some processors with an embedded core have enough power to run undemanding games. However, they will not work for demanding games or video editing; you need a discrete graphics card.

CPU vs. GPU performance: What’s the Difference?

GPU

The Graphics processing unit is the image processor. The workflow and physical structure of the CPU and GPU are roughly similar. Compared to the CPU, the work of the GPU is more unitary. In most personal computers, the GPU is only used to draw images. If the CPU wants to draw a two-dimensional graph, it only needs to send an instruction to the GPU, and the GPU can quickly calculate all the pixels of the graph and draw the corresponding graph at the specified position on the display. Since the GPU generates a lot of heat, there is usually a separate heat sink on the graphics card.

Design structure

The CPU has a powerful arithmetic operation unit, which can complete arithmetic calculations in a few clock cycles. At the same time, a large cache can store a lot of data in it. Also, complex logic control units reduce the delay by providing branch prediction capabilities when they have multiple branches. GPU is based on a large throughput design, with many arithmetic operation units and very few caches. At the same time, the GPU supports a large number of threads running at the same time. If they need to access the same data, the cache will merge these accesses, which will naturally cause delay problems. Despite the delay, it can achieve a huge throughput effect because of the large number of arithmetic operation units.

Scenes to be used

Obviously, because the CPU has many caches and complex logic control units, it is very good at logic control and serial operations. In comparison, GPU has a large number of arithmetic operation units to perform a large number of calculations simultaneously. It is good at large-scale concurrent calculations. The calculation is large, but there is no technical content, and it has to be repeated many times. In this way, the way we use GPU to increase the speed of program operation is obvious. Using CPU to do complex logic control and GPU to do simple but large arithmetic operations can greatly improve its running speed.

Conclusion about the best CPU

When choosing a processor, of course, it is necessary to consider the tasks that are planned to be solved using a computer. If you need a new computer to browse the Internet, watch movies and listen to music, then a single-core processor or dual-core processor is enough. But if you plan to work with video editing, 3D graphics, processing large amounts of data, then, in this case, it is better to buy at least a quad-core one.

High power in a single-core. The Core i3, i5, i7, and i9 range are perfect for those looking for the best strength in processes requiring high performance or Overclocking. And this is where Intel completely takes the cake, especially when it comes to gaming.

Suppose you are going to “upgrade” your computer or replace a processor that has failed. In that case, you need to pay great attention to the existing configuration of the computer, and especially the motherboard socket. If you have a low-power graphics processing unit (GPU) or little RAM, then even buying a new powerful “stone,” you are unlikely to get a significant increase in computer performance. Absolutely all components of the hardware computer affect this.