What does computer performance mainly depend on?

The performance of a computer mainly depends on: word length, operation speed (number of instructions that can be executed per second), internal memory capacity, external memory capacity, I/O speed, video memory, and hard disk Rotation speed, CPU main frequency (clock frequency at which the CPU core works).

The function or performance of a microcomputer is not determined by a certain indicator, but by its system structure and instructions. It is comprehensively determined by many factors such as system, hardware composition, and software configuration. But for most ordinary users, the performance of the computer can be generally evaluated from the following indicators.

1. Computing speed

Computing speed is an important indicator of computer performance. The commonly referred to computer computing speed (average computing speed) refers to the number of instructions that can be executed per second, which is generally described as "million instructions/second" (mips, MillionInstructionPerSecond). The same computer may take different times to perform different operations, so different methods are often used to describe the operation speed. Commonly used ones include CPU clock frequency (clock frequency), average number of instructions executed per second (ips), etc. Microcomputers generally use the main frequency to describe the computing speed. For example, the main frequency of Pentium/133 is 133 MHz, the main frequency of Pentium III/800 is 800 MHz, and the main frequency of Pentium 41.5G is 1.5 GHz. Generally speaking, the higher the main frequency, the faster the computing speed.

2. Word length

The group of binary numbers processed by the computer at the same time is called the "word" of a computer, and the number of digits in this group of binary numbers is the "word length". All other indicators being equal, the larger the word length, the faster the computer can process data. The word lengths of early microcomputers were generally 8 and 16 bits. Currently, most 586s (Pentium, PentiumPro, PentiumII, PentiumIII, Pentium4) are 32-bit, and most people now have 64-bit installed.

3. Internal memory capacity

Internal memory, also referred to as main memory, is a memory that the CPU can directly access. Programs that need to be executed and data that need to be processed are stored in the main memory. . The size of internal memory reflects the computer's ability to store information instantly. With the upgrade of operating systems, the continuous enrichment of application software and the continuous expansion of functions, people's demand for computer memory capacity is also constantly increasing. Currently, running the Windows95 or Windows98 operating system requires at least 16M of memory capacity, while WindowsXP requires more than 128M of memory capacity. The larger the memory capacity, the more powerful the system is and the larger the amount of data it can handle.

4. Capacity of external memory

External memory capacity usually refers to the hard disk capacity (including built-in hard disk and removable hard disk). The larger the external memory capacity, the more information can be stored and the richer the application software that can be installed. At present, hard disk capacity generally ranges from 10G to 60G, and some have even reached 120G.

5. I/O speed

The speed of host I/O depends on the design of the I/O bus. This does not matter much for slow devices (such as keyboards and printers), but the effect is very obvious for high-speed devices. For example, for the current hard disk, its external transfer rate has reached more than 20MB/S and 4OMB/S.

6. Video memory

The performance of video memory is determined by two factors, one is capacity and the other is bandwidth. Capacity is easy to understand. Its size determines how much data can be cached. In terms of bandwidth, it can be understood as the channel for exchanging data between the video memory and the core. The larger the bandwidth, the faster the data exchange. Therefore, capacity and bandwidth are key factors in measuring video memory performance.

In addition, the bandwidth is determined by two factors: frequency and bit width. The calculation formula is: bandwidth = frequency X bit width/8. For example, for two graphics cards with the same core and memory capacity, the memory of card 1 is DDR3 1600MHz frequency and 128 bits wide; the memory of card 2 is DDR2 800MHZ frequency and 256 bits wide. It seems that the memory parameters of the two are different, but through formula calculation, both have a bandwidth of 25.6G/S and the performance is the same. Therefore, as long as we understand the essence, no matter how complex and changeable the product is, it cannot fool us.

Video memory capacity: Common capacities are 128M, 256M, 512M, 896M, 1G, etc. The larger the capacity, the more data can be cached.

Video memory frequency: Generally there are several types such as DDR2, DDR3, GDDR3, GDDR5, etc. GDDR5 has the highest frequency, and the equivalent frequency can reach more than 4GHZ. DDR2 frequency is the slowest, some even only 667MHZ.

Video memory bit width: Generally there are 64bit, 128bit, 256bit, 448bit, 512bit, etc. The larger the bit width, the more difficult it is to manufacture and the higher the cost. Therefore, many times manufacturers would rather choose a combination of low bit width and high frequency, which can reduce costs while ensuring performance (common in A-card products).

7. Hard drive speed

RotationalSpeed ​​is the rotation speed of the motor spindle in the hard drive, which is the maximum number of revolutions that the hard drive platter can complete in one minute. The speed of rotation is one of the important parameters that indicates the grade of the hard disk. It is one of the key factors that determines the internal transmission rate of the hard disk and directly affects the speed of the hard disk to a large extent.

The faster the hard disk rotates, the faster the hard disk searches for files, and the relative transmission speed of the hard disk is also improved.

The hard disk speed is expressed in revolutions per minute, and the unit is RPM. RPM is the abbreviation of Revolutions Perminute, which is revolutions per minute. The larger the RPM value, the faster the internal transfer rate, the shorter the access time, and the better the overall performance of the hard drive. The spindle motor of the hard disk drives the platter to rotate at high speed, creating buoyancy that causes the magnetic head to float above the platter. To bring the sector of data to be accessed under the head, the faster the rotation speed, the shorter the waiting time. Therefore, the rotational speed determines the speed of the hard drive to a large extent.

8. Main frequency

The main frequency of the CPU is the clock frequency at which the CPU core works. What is usually said is the MHz of a certain CPU, and this MHz is the "main frequency of the CPU".

There is a certain relationship between the main frequency and the actual computing speed, but there is no definite formula that can quantify the numerical relationship between the two, because the computing speed of the CPU also depends on the performance indicators of various aspects of the CPU's pipeline. (Cache, instruction set, number of CPU bits, etc.). Since the main frequency does not directly represent the computing speed, under certain circumstances, a CPU with a higher main frequency may have a lower actual computing speed. For example, most of AMD's AthlonFX series CPUs can achieve the higher frequency CPU performance of Intel's Pentium 4 series CPUs at lower clock speeds, so the AthlonFX series CPUs are named after PR values. Therefore, the main frequency is only one aspect of CPU performance and does not represent the overall performance of the CPU.

The main frequency of the CPU does not represent the speed of the CPU, but increasing the main frequency is crucial to increasing the CPU's computing speed. For example, assuming a CPU executes an arithmetic instruction in one clock cycle, when the CPU runs at a main frequency of 100MHz, it will be twice as fast as when it runs at a main frequency of 50MHz. Because the 100MHz clock cycle takes up half the time compared to the 50MHz clock cycle, that is, the time required for a CPU working at a 100MHz main frequency to execute an operation instruction is only 10 ns, which is half shorter than the 20 ns when working at a 50 MHz main frequency. Natural computing The speed is twice as fast. However, the overall running speed of the computer not only depends on the CPU computing speed, but also is related to the operation of other sub-systems. Only by increasing the main frequency, the running speed of each sub-system and the data transmission speed between sub-systems can be improved. After it is improved, the overall running speed of the computer can really be improved.

Increasing the CPU working frequency is mainly limited by the production process. Since the CPU is manufactured on a semiconductor silicon wafer, wires are required to connect the components on the silicon wafer. Under high-frequency conditions, the wires are required to be as thin and short as possible, so as to reduce stray interference such as wire distributed capacitance. To ensure that the CPU operation is correct. Therefore, the limitation of manufacturing process is one of the biggest obstacles to the development of CPU frequency. The more mainstream memory frequencies are 667MHz and 800MHz DDR2 memory, and 1333MHz DDR3 memory. The higher-end ones are calculated in GHz. For example, the main frequency required by high-end enterprises is ≥2.4GHz.

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