Graphics card knowledge

Graphics card knowledge

Graphics card knowledge introduction

First, look at n or a.
A is ATI series and N is nVIDIA series.
Graphics card chip: such as GeForce 7300GT.
Graphics memory type: DDRII or DDRIII.
Graphics memory bit width and memory capacity: 128-bit/128M 256-bit/128M 256-bit/256M.
Bus interface: PCI-E or AGP. PCI-E has 1X to 16X. The speed is up to 8000.
This is the most intuitive


. Interface type refers to the type of interface used to connect the graphics card to the motherboard. The interface of the graphics card determines the maximum bandwidth of data transmission between the graphics card and the system, that is, the maximum amount of data that can be transmitted instantly. Different interfaces determine whether the motherboard can use this graphics card. The graphics card can only be used if there is a corresponding interface on the motherboard, and different interfaces can bring different performance to the graphics card.
At present, various 3D games and software have higher and higher requirements for graphics cards, and the amount of data that needs to be exchanged between the motherboard and the graphics card is also increasing. The graphics card interface in the past can no longer meet such a large amount of data exchange, so the motherboard usually has a slot dedicated to inserting the graphics card. If the transmission speed of the graphics card interface cannot meet the needs of the graphics card, the performance of the graphics card will be greatly limited, and no matter how good the graphics card is, it will not be able to perform well. Since the development of graphics cards, there have been several interfaces such as ISA, PCI, AGP, and PCI Express, and the data bandwidth they can provide has increased successively. Among them, the PCI Express interface launched in 2004 has become the mainstream to solve the bottleneck problem of data transmission between graphics cards and systems, while graphics cards with ISA and PCI interfaces have been basically eliminated. The
maximum resolution of a graphics card refers to the number of pixels that the graphics card can depict on the monitor. As we all know, the picture displayed on the monitor is composed of pixels, and all the data of these pixels is provided by the graphics card. The maximum resolution is the number of pixels that the graphics card outputs to the monitor and can depict on the monitor. The larger the resolution, the more pixels of the image that can be displayed, and the more details can be displayed, and of course the clearer it is.
The maximum resolution is directly related to the video memory to a certain extent, because the data of these pixels must be stored in the video memory at first, so the video memory capacity will affect the maximum resolution. In the early days when the video memory capacity of graphics cards was only 512KB, 1MB, 2MB, etc., the video memory capacity was indeed a bottleneck for the maximum resolution; but the video memory capacity of mainstream graphics cards has been eliminated, even 64MB, and mainstream entertainment-level graphics cards are already 128MB, 256MB or 512MB, and some professional graphics cards even have 1GB of video memory. In this case, the video memory capacity is no longer a factor affecting the maximum resolution. The reason why such a large capacity of video memory is needed is that now large-scale 3D games and professional rendering need to temporarily store more data. Now
the maximum resolution is actually determined by the RAMDAC frequency of the graphics card. At present, the RAMDAC of all mainstream graphics cards has reached 400MHz, which can at least reach the maximum resolution of 2048x1536, and the maximum resolution of the latest generation of graphics cards is as high as 2560x1600.
In addition, the maximum display resolution that the graphics card can output does not mean that your computer can achieve such a high resolution. It must also be matched with a powerful enough monitor. In other words, the maximum resolution of the monitor must match the maximum resolution of the graphics card to achieve it. For example, to achieve a resolution of 2048x1536, in addition to the graphics card, the monitor must also support it. The maximum resolution of a CRT monitor is mainly determined by its bandwidth, while the maximum resolution of an LCD monitor is mainly determined by its panel. For the current mainstream monitors, the maximum resolution of a 17-inch CRT is generally only 600x1200, and the maximum resolution of a 17-inch and 19-inch LCD is only 1280x1024. Therefore, the bottleneck of the maximum resolution on ordinary computer systems is not the graphics card but the monitor. To achieve a maximum resolution of 2048x1536 or even 2560x1600, it can only be achieved with the help of a professional-grade large-screen high-end monitor. For example, DELL's 30-inch LCD monitor can achieve an ultra-high resolution of 2560x1600.
The display chip is the core chip of the graphics card. Its performance directly determines the performance of the graphics card. Its main task is to process the video information input by the system and build and render it. The performance of the display main chip directly determines the performance of the display card. Different display chips have differences in both internal structure and performance, and their prices vary greatly. The status of the display chip in the graphics card is equivalent to that of the CPU in the computer, and it is the core of the entire graphics card. Due to the complexity of the display chip, the manufacturers that currently design and manufacture display chips are only NVIDIA, ATI, SIS, 3DLabs and other companies. Home entertainment graphics cards all use single-chip display chips, while some professional workstation graphics cards use a combination of multiple display chips. The
display chip bit width refers to the bit width of the data bus inside the display chip, that is, the number of data transmission bits used inside the display chip. Currently, mainstream display chips basically use a bit width of 256 bits. Using a larger bit width means that the amount of data that can be transmitted instantly is greater when the data transmission speed remains unchanged. It is like valves of different calibers. Under the condition of a certain water flow rate, the larger the caliber, the greater the water output. The display chip bit width is the bandwidth of the internal bus of the display chip. The larger the bandwidth, the faster the computing power and data throughput that can be provided. It is one of the important data that determines the level of the display chip. The largest display chip bit width currently launched is 512 bits, which is the Parhelia-512 graphics card launched by Matrox. This is the world's first display chip with a 512-bit width. All mainstream display chips in the market, including NVIDIA's GeForce series graphics cards and ATI's Radeon series, all use a 256-bit bit width. The two largest display chip manufacturers in the world will also adopt 512-bit width in the next few years.
The increase in the bit width of the display chip does not mean that the chip has stronger performance, because the display chip is highly integrated, and the design and manufacturing require high technical capabilities. Simply emphasizing the bit width of the display chip does not make much sense. Only when other components, chip design, manufacturing process, etc. are fully coordinated, the role of the display chip bit width can be reflected. The video memory bit width
is the number of bits of data that the video memory can transmit in one clock cycle. The larger the bit, the greater the amount of data that can be transmitted instantly. This is one of the important parameters of the video memory. At present, there are three types of video memory bus widths on the market: 64-bit, 128-bit, and 256-bit. People usually call them 64-bit graphics cards, 128-bit graphics cards, and 256-bit graphics cards, which refer to their corresponding video memory bus widths. The higher the video memory bus width, the better the performance and the higher the price. Therefore, 256-bit video memory is more used in high-end graphics cards, while mainstream graphics cards basically use 128-
bit video memory. As we all know, video memory bandwidth = video memory frequency X video memory bus width / 8, so when the video memory frequency is the same, the video memory bus width will determine the size of the video memory bandwidth. For example, if the video memory frequency of 128-bit and 256-bit video memory is 500MHz, then their video memory bandwidths will be: 128-bit = 500MHz*128∕8 = 8GB/s, and 256-bit = 500MHz*256∕8 = 16GB/s, which is twice that of 128-bit. It can be seen that the video memory bus width is important in video memory data.
The video memory of a graphics card is composed of memory chips. The total bit width of the video memory is also composed of the bit width of the memory particles. Video memory bit width = video memory particle bit width × number of video memory particles. The video memory particles are all marked with the memory number of the relevant manufacturer. You can go online to find out its bit width, and then multiply it by the number of video memory particles to get the bit width of the graphics card. This is the most accurate method, but it is more troublesome to implement.
The video memory clock cycle is the repetition period of the video memory clock pulse, which is an important indicator to measure the speed of the video memory. The faster the video memory speed, the larger the amount of data exchanged per unit time, and the graphics card performance will be significantly improved under the same conditions. The clock cycle of the video memory is generally in ns (nanoseconds), and the operating frequency is in MHz. The video memory clock cycle corresponds to the operating frequency one by one, and the relationship between them is: operating frequency = 1 ÷ clock cycle × 1000. If the video memory frequency is 166MHz, then its clock cycle is 1 ÷ 166 × 1000 = 6ns.
For DDR SDRAM or DDR2, DDR3 video memory, the equivalent output frequency is used to describe its operating frequency. Because data can be transmitted on both the rising and falling edges of the clock cycle, the video memory bandwidth is twice that of SDRAM when the operating frequency and data bit width are the same. In other words, when the video memory clock cycle is the same, the equivalent output frequency of DDR SDRAM video memory is twice that of SDRAM video memory. For example, the operating frequency of 5ns SDRAM video memory is 200MHz, while the equivalent operating frequency of 5ns DDR SDRAM or DDR2, DDR3 video memory is 400MHz. Common video memory clock cycles are 5ns, 4ns, 3.8ns, 3.6ns, 3.3ns, 2.8ns, 2.0ns, 1.6ns, 1.1ns, or even lower.
The core frequency of a graphics card refers to the operating frequency of the display core, and its operating frequency can reflect the performance of the display core to a certain extent. However, the performance of a graphics card is determined by many factors such as the core frequency, video memory, pixel pipeline, pixel fill rate, etc. Therefore, in the case of different display cores, a high core frequency does not mean that the performance of this graphics card is strong. For example, the core frequency of 9600PRO reaches 400MHz, which is higher than the 380MHz of 9800PRO, but in terms of performance, 9800PRO is definitely better than 9600PRO. Among chips of the same level, those with higher core frequencies have stronger performance. Increasing the core frequency is one of the methods of overclocking graphics cards. There are only two mainstream display chip manufacturers, ATI and NVIDIA. Both companies provide display cores to third-party manufacturers. Under the same display core, some manufacturers will appropriately increase the display core frequency of their products so that they work at a higher frequency than the fixed frequency of the display core to achieve higher performance.