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1. Friend, I understand your question
to put it this way, you have made a mistake:
in this formula, the unit meaning of frequency and bit width of video memory is different
the "bit / 8" of the bit width of the video memory should be understood as "number" in the calculation, while the "MHz" in the frequency of the video memory should be understood as "quantity in each"
when calculating, we should not replace "bit / 8" in the bit width of the video memory with "GB"
because the unit in the formula is "bit / 8" for the bit width and "GB" for the frequency
in this way, 500 * 128 / 8 = 8000MB / S is calculated
this formula of video memory bandwidth can also be written as "MHz * byte"

2. 1. Graphics card

is also known as: video card, video adapter, graphics card, graphics adapter and display adapter, etc. It is a "bridge" between the host computer and the display. It controls the graphics output of the computer, processes the image data sent by the CPU into the format recognized by the display, and then sends it to the display to form an image. The video card is mainly composed of display chip (graphic processing unit), video memory, RAMDAC, VGA BIOS and various interfaces. The following will be introced to each part<

2. Display chip

graphics processing chip, also known as GPU (graphic processing unit). It is the "brain" of the graphics card, responsible for most of the calculation work. In the whole graphics card, GPU is responsible for processing the data sent by the computer, and finally displays the results on the display. All kinds of 3D special effects supported by a graphics card are determined by the performance of GPU, which is also equivalent to the role of CPU in the computer. What kind of display chip a graphics card uses roughly determines the grade and basic performance of the graphics card. It is also the basis for distinguishing 2D display card from 3D display card. 2D display chips mainly rely on the processing power of CPU when processing 3D images and special effects, which is called "soft acceleration". The 3D display chip is the so-called "hardware acceleration" function, which integrates the three-dimensional image and special effect processing functions in the display chip. Now most of the graphics cards in the market use NVIDIA and ATI's graphics processing chips, such as NVIDIA FX5200, fx5700, radius 9800 and so on. However, although the display chip determines the grade and basic performance of the graphics card, the performance of the graphics card can be brought into full play only with the appropriate display memory

3. Video memory

full name display memory, which is basically the same as the memory function on the motherboard. Video memory is divided into frame cache and material cache, which is usually used to store the data information and material information processed by the display chip (Group). When the display chip processes the data, it will send the data to the video memory, and then RAMDAC reads the data from the video memory, converts the digital signal into the analog signal, and finally outputs it to the display screen. Therefore, the speed and bandwidth of the video memory directly affect the speed of a video card. Even if your graphics chip is very powerful, if the on-board video memory can not meet the requirements and the processed data can not be transferred immediately, then you will not get satisfactory display effect. The capacity and speed of the video memory are directly related to the performance of the video card. The high-speed video card chip has a higher capacity for the video memory, so the quality of the video memory is also an important index to measure the performance of the video card. In order to evaluate the performance of a video memory, we mainly analyze it from the following aspects: type, working frequency, package and bit width of video memory:

(1) brand of video memory

at present, Samsung and Hynix are the most popular video cards in the market, and other video cards are also used, such as atrontech, Infineon, micron, etc Elitemt / ESMT and other brands are relatively powerful manufacturers with guaranteed quality< At present, SDRAM and DDR SDRAM are widely used. And SDRAM has been basically eliminated, the mainstream is DDR SDRAM

DDR SDRAM: DDR is the abbreviation of double data rate, which is an evolution of the existing SDRAM. DDR can transmit data on both the rising and falling edge of the clock cycle, while SDRAM can only transmit data on the rising edge, so the bandwidth of DDR is twice that of SDRAM. Therefore, in theory, the data transmission rate of DDR is twice that of SDRAM. In the case of the same video memory speed, if the frequency of SDRAM is 166MHz, the frequency of DDR is 333mhz. Now DDR has developed to DDRII or even DDRII, and some high-end graphics cards begin to use DDRII or DDRII memory

(3) video memory packaging methods

there are three kinds of video memory packaging forms: TSOP (thin small out line package), QFP (Quad Flat Package) and microbga (micro ball grid array). At present, the mainstream graphics cards are basically packaged with TSOP and MBGA, and most of them are packaged with TSOP.

TSOP packaging method: the full name of TSOP is "thin small out line package", that is, "thin small out line package", which makes pins around the packaging chip. This kind of packaging can rece parasitic parameters, and is suitable for high frequency applications, with convenient operation and high reliability, Is a relatively mature packaging technology, but also the most common in the market

microbga packaging: also known as 144pin FBGA, 144-bar FBGA (fine pitch ball grid array) packaging technology, different from TSOP, its pins are not exposed, so we can't see this kind of video memory, and we can't see the pins. The actual footprint of the memory chip particles in this package is relatively small. The advantage of this packaging technology is that it will bring better heat dissipation and overclocking performance. Therefore, professionals can basically estimate the overclocking potential of this graphics card as soon as they see the packaged memory. This is because the pin pins of the video memory are all under the chip, so the electrical connection is short, the electrical performance is good, and it is not easy to be disturbed. At present, most high-speed memory, video memory particles are using this packaging method

(4) video memory capacity

when we often talk about a video card, we usually say that it is 64M 128bit or 128MB 128bit. Here 64MB or 128MB refers to the video memory capacity of the video card. Now the mainstream video card basically has 64MB or 128MB capacity, and a few high-end video cards have 256MB capacity. Just like the system memory, the more capacity the video memory has, the better. Because the larger the video memory is, the more image data it can store, the higher the resolution and color number it supports, and the smoother the game will run. However, sometimes the more video memory, the better. For graphics cores with different architectures and capabilities, the demand for video memory capacity is also different. The graphics core with powerful data processing capability needs more display memory when using anti aliasing and other additional functions to improve the image quality. However, for some low-end graphics cards, e to the limitation of architecture, even increasing the memory capacity can not significantly increase the performance, and more capacity can only increase the cost

(5) the speed of video memory

the speed of video memory takes ns (nanosecond) as the unit of calculation. Now the common video memory is between 6ns and 2ns. The faster the number is, the faster the speed of video memory is. The corresponding theoretical working frequency can be expressed by the formula: working frequency (MHz) = 1000 / video memory speed (in case of DDR video memory, working frequency (MHz) = 1000 / video memory speed x2). For example, the working frequency of 5ns video memory is 1000 / 5 = 200MHz. If the DDR specification is used, its frequency is 200x2 = 400MHz. Now the main graphics card is the use of DDR specifications of the video memory

6) video memory bandwidth

video memory bandwidth refers to the amount of data that can be read in at a time, that is, the speed of data exchange between video memory and display chip. The larger the bandwidth is, the better the & quot; Pathway & quot; The wider the data, the better the data; Running & quot; It's smoother and won't cause blockage. Video bandwidth can be calculated by the following formula: video frequency × Video memory bit width / 8 (divided by 8 because every 8 bits equals one byte). The bit width of video memory refers to the bit width of the interface between video memory and external data exchange, and refers to the number of bits that can be transmitted in a clock cycle. From the above formula, we can see that the bit width of video memory is an important factor determining the bandwidth of video memory, which is related to the performance of video card. We often say that a graphics card is of 64MB 128bit specification, of which 128bit means that the graphics memory of the card is wide. At present, most of the graphics cards on the market have a bit width of 128bit (some are 64bit), and some high-end cards even have a bit width of 256bit< The function of RAMDAC is to convert the digital signal in the display memory into the analog signal that can be used for display. The speed of RAMDAC has a great influence on the image seen on the display. This is mainly because the refresh rate of the image depends on the analog information received by the display, which is provided by RAMDAC. RAMDAC conversion rate determines the refresh rate. But now most of the video card RAMDAC are integrated in the main chip, less see independent RAMDAC chip

5. The BIOS of the graphics card is VGA BIOS, which is similar to the BIOS of the motherboard. Every graphics card has a BIOS. There is usually a small memory chip on the graphics card to store the control program between the display chip and the driver. In addition, there is information about the model, specification, manufacturer and factory of the graphics card. The BIOS of graphics card is directly related to the overclocking of graphics card

6. Bus interface

the graphics card must be inserted on the motherboard to exchange data with the motherboard, so it must have the corresponding bus interface. Now the most popular bus interface is AGP interface. AGP (accelerated graphics prot) interface is a special display interface based on PCI graphics interface. It has the characteristics of exclusive bus. Only image data can pass through AGP port. AGP is divided into AGP 8x, AGP 4x and AGP 2x. Now AGP 8x has become the mainstream, with a bus bandwidth of 2133mb / s, which is twice that of AGP 4x

the current motherboard is basically AGP 8x specification, and AGP 8x specification is compatible with AGP 4x, that is, AGP 8x slot can be inserted into AGP 4x graphics card, and AGP 8x graphics card can also be used in AGP 4x slot motherboard<

recently, Intel has launched the latest PCI-E graphics card interface, with a bus bandwidth of up to 4G / s. however, it may take a long time for it to be popularized. You can go to DIY column to see the relevant article: summary of Computex graphics card (PCI-E)

7. Output interface

if the image processed by the graphics card is to be displayed on the display device, it cannot be separated from the output interface of the graphics card. Now the most common output interfaces are: VGA interface, DVI interface and S terminal< (1) VGA (Video Graphics Array) interface, namely d-sub15 interface, is used to output the converted analog signal to CRT or LCD display. Now almost every video card has a standard VGA interface, because most domestic monitors, including LCD, use VGA interface as the standard input mode. The standard VGA interface adopts 15 pin connection mode with asymmetric distribution. Its working principle is that the image signal stored in digital format in the video memory is analog molated into analog high frequency signal in RAMDAC, and then output to the display for imaging. Its advantages include no crosstalk, no circuit synthesis separation loss and so on

(2) DVI (digital visual interface digital video interface) interface, the video signal does not need to be converted, the signal does not decay or distortion, the display effect is improved significantly, will be the replacement of VGA interface. VGA is based on analog signal transmission. The process of digital to analog conversion and analog transmission will bring a certain degree of signal loss. DVI interface is a complete digital video interface, which can generate video card

3. Bit width is the amount of data that memory or video memory can transmit at one time. In short, it is the width of data that can be transmitted at one time, just like the lane width of highway, two-way four lane and two-way six lane. Of course, the more lanes there are, the larger the cars can pass at one time. Therefore, the larger the bit width is, the more data can be transmitted at one time. For the graphics card, the performance improvement is obvious
the bit width of the video memory is the number of bits that the video memory can transmit data in a clock cycle. The larger the number of bits, the greater the amount of data that can be transmitted instantly. This is one of the important parameters of the video memory
the so-called memory bandwidth refers to the data transmission capability provided by the memory bus, but it depends on the memory chip and memory mole rather than the pure bus design. In addition, it plays an important role and is often discussed as a separate object<

extended data:
bit width classification:
there are six kinds of common video memory bit widths in the market: 128 bit, 192 bit, 256 bit, 384 bit, 512 bit and 1024 bit. The 128 bit, 256 bit video card, 384 bit video card, 512 bit video card and 1024 bit video card are the corresponding video memory bit widths
the higher the display memory bit width is, the better the performance and the higher the price will be. Therefore, the display memory with medium and high bit width is more used in high-end graphics cards, while ordinary graphics cards basically use 128 bit display width, while 1024 bit graphics cards belong to the top class.

4.

There is no necessary relationship between the display card bit width and the display memory. These two are the reference factors to measure the performance of the display card:

1. the display card bit width refers to the display memory bit width, that is, the number of bits that can be transmitted in a clock cycle. The larger the number of bits, the greater the amount of data that can be transmitted instantaneously

2. video memory, also known as frame buffer, is used to store the rendering data processed or to be extracted by the graphics chip. Like the memory of a computer, the video memory is used to store the graphic information to be processed

   
   

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in addition to the above two factors, the reference factors for measuring the performance of graphics card include frequency, video memory bandwidth and stream processor

1. frequency: frequency is the speed of the graphics card processing data and the speed of exchanging data with GPU. The unit is ns or MHz, 1ns = 1000 / 1MHz. The faster the frequency of the graphics memory is, the more channels there are, the more data can be processed at the same time, and the better the performance of the graphics card

2. video memory bandwidth: video memory bandwidth refers to the data transmission rate between the display chip and video memory, in bytes per second. Video memory bandwidth is one of the most important factors to determine the performance and speed of video card

3. stream processor: stream processor is the pixel rendering pipeline and vertex coloring unit, also called SP unit. Its function is to process the data transmitted by CPU and convert it into digital signal that can be recognized by the display. Of course, the higher the stream processor, the better< br />

5. The bit width of video memory is the number of bits that can transmit data in a clock cycle. The larger the number of bits, the larger the amount of data that can be transmitted instantly. This is one of the important parameters of video memory. At present, there are three kinds of video memory bit width in the market, namely 64 bit, 128 bit and 256 bit. People usually call them 64 bit, 128 bit and 256 bit video cards. The higher the bit width of video memory, the better the performance and the higher the price. Therefore, 256 bit video memory is more used in high-end video cards, while 128 bit video memory is basically used in mainstream video cards

as we all know, video memory bandwidth = video memory frequency x video memory bit width / 8, then when the video memory frequency is the same, the video memory bit width will determine the size of the video memory bandwidth. For example, 128 bit and 256 bit video memory with the same frequency of 500MHz will have 128 bit = 500MHz * 128 ／ 8 = 8GB / s, while 256 bit = 500MHz * 256 ／ 8 = 16GB / s, which is twice of 128 bit. It can be seen that the bit width of video memory is important in video memory data

the video memory of a video card is composed of a block of video memory chips, and the total bit width of the video memory is also composed of the bit width of the video memory particles,. Display memory width = display memory particle width × The number of video memory particles. The memory number of the relevant manufacturer is on the video memory granule. You can find the number on the Internet to understand its bit width, and then multiply it by the number of video memory granule to get the bit width of the video card. This is the most accurate method, but it is troublesome to implement.

the following one is relatively simple, but only suitable for general situations. There are some special situations, which can be applied in most cases. At present, there are mainly two kinds of video memory packages: TSOP and BGA. Generally, the video memory in BGA package is 32 bits per chip, while the video memory in TSOP package is 16 bits per chip/ It's a big one. If the graphics card uses four BGA packages, its bit width is 128 bits. If the graphics card uses eight TSOP packages, its bit width is 128 bits. But if the graphics card only uses four TSOP packages, its bit width is only 64 bits. This is just a general skill, not necessarily in line with all the circumstances, to do the most accurate judgment, or look at the memory number it!

7.

bus line: no.363, the whole journey is about 4.6km

1. Walk about 90m from Changchun medical insurance management station to Guilin Road Station

2. Take no.363, pass 4 stops, reach Baixiang shoe city station

3. Walk about 590m, reach Ping Street

2

8. The geographical location of the municipal medical insurance bureau, you can open the network map to view.

9. Call the local information desk to find out the phone number.