Graphics card

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A graphics card, video card, v card, video board, video display board, display adapter, video adapter, or graphics adapter [1] is a computer component designed to convert the logical representation of visual information into a signal that can be used as input for a display medium. Displays are most often a monitor, but use of LCD TV, HDTVs, and projectors is growing increasingly common with the growth of the media center computer concept. The graphics card and display medium are able to communicate utilizing a variety of display standards. Graphics cards are both integrated into motherboards, and sold as expansion cards.

1 History
2 Card types
3 Uses
- 3.1 Conventional 2D
- 3.2 3D gaming and rendering
4 Manufacturers
5 External links

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History

The original hardware accelerated 3D renderers came on a board that was used in conjunction with a normal graphics card. The cards added 3D graphics to the 2D rendering from the graphics card via a pass-through cable.

One of the major players in graphics card history was the Hercules Graphics Adapter (HGC). It offered text mode of 80x25 and high quality monochromatic images of up to 720x348.

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Card types

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Integrated

In today's OEM computer market, graphics cards are often substituted for an integrated graphics chip on a section of the motherboard. Sometimes the graphics chip is located on the Northbridge chip, if present, and uses either its own dedicated memory or more usually a portion of the system memory (shared memory). Increasingly, it is possible to select the amount of shared memory to be used via the BIOS. Integrated-graphics-displays typically have inferior 3D performance compared to dedicated graphics cards due to the use of cheaper chipsets and sharing system memory rather than using dedicated memory. This is not always the case, as evidenced in higher-end integrated solutions, such as game-oriented laptop architectures. Those who require high performance still prefer non-integrated solutions.

Integrated graphics displays have gradually become more common in pre-built computer systems since the mid 1990s as computer manufacturers such as Hewlett-Packard and Dell look for ways to cut costs while still providing basic video support. In terms of office tasks, web-browsing, email and similar computer activities, integrated graphics displays are a more practical solution than high-powered 3D graphics cards. First person shooter games like DOOM relied on high-performance cards at the time the game was introduced.

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Expansion

The most powerful graphics hardware, usually geared towards 3D graphics for games, is typically found on expansion cards. Their processing engines are sometimes called GPUs (graphics processing units), or, most commonly used by ATI Technologies, VPU's (Visual Processing Units). The longterm goal of graphics cards manufacturers (and game developers) appears to be realtime photorealistic rendering. New products and technologies are often touted to provide "Hollywood quality" - 3dfx used claims of movie-quality effects to promote their Voodoo 5 cards with T-Buffer technology, allowing motion blur, depth of field and full screen anti-aliasing effects. nVIDIA talked about "the dawn of cinematic computing" when introducing its GeForce FX chip with the Dawn technology demo. Others use the new technology for more stylised and unique but unrealistic rendering, such as cel shading.

The most common connection for video cards for current mainboards is PCI Express, which is taking over from the previous Accelerated Graphics Port, or AGP. Older video cards used PCI which was more limited on bandwidth than AGP or PCI Express.

AGP is only allowed to send up to 35 watts of power to the video card using it, and therefore some higher end cards required a seperate power connection. This was supposed to be fixed when PCI Express was designed, with a maximum power raised to 75 watts. However, modern cards have now eclipsed that barrier, and therefore still require a separate power connection.

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What makes it fast?

Modern 3D graphics cards relay on the values of many variables in order to determine their speed. The most important of these variables are; clock speed, memory speed, and pixel processing volume.

The clock speed is the frequency with which the GPU or VPU operates at. This can be anywhere in a large range and can be compared to the operating frequency of a CPU. The memory clock is another way of determining how fast a card will operate. The memory clock is also measured in Mhz (megahertz), but will sometimes have a theoretical mutlipler associated with it. If your video card is operating with SDRAM then the effective speed is the same at the clock speed. If you have DDR-SDRAM then the effective frequency is twice that of the clock speed. For example, if you have an nVIDIA 6800gs with a 525Mhz memory clock, it effectively operates at 1050Mhz.

One very important card specification that is often overlooked is the number of pixel pipelines. If a card has 8 pixel pipelines, a clock speed of 400Mhz, and a memory clock of 1000Mhz, it if often slower than a card with 12 pipelines and lower clock amd memory clock values. This is one of the main ways a consumer can tell where their card falls in the spectrum of end-user graphics cards. Manufacturers can overclock their cards without a problem; but they cannot add pixel pipelines, and therefore higher end cards almost always have a higher pipeline count, allowing for higher volumes of data to be processed and rendered.

There are other variables like memory architecture, and memory technology. Memory architecture is normally a value of 128-bit, or 256-bit with the latter being on the higher end, higher performance cards. Memory technology refers to the type of DDR-SDRAM or SDRAM available. The highest end gaming graphics cards are using GDDR3 which stands for Graphics Dual Data Rate Synchronous Dynamic RAM, Generation 3.

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Uses

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Conventional 2D

Conversely, sometimes 3D graphics capabilities are not relevant to the choice of high-performance graphics card. The current generation of desktop software and operating systems works exclusively with 2D graphics. Specialised niches in areas such as medical imaging also require 2D graphics and fine visual-quality.

With the upcoming Windows Vista operating system, the images in the Windows OS will be rendered by using vector graphics instead of bitmap graphics, or raster graphics. Currently, this is a task that the CPU or Central Processing Unit of your pc is assigned to complete. This new operating system will require that its main 2D graphics processing will be taken over by the GPU or Graphics Processing Unit.

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3D gaming and rendering

3D cards for model rendering in art and animation are different from those intended for games. While they may have similar hardware, their drivers and firmware are optimized for the specific task. Rendering cards are tuned for high precision, and gaming cards provide high performance. A digital or analog monitor may be connected to the graphics card via a DVI connector or VGA connector respectively. Increasingly, the higher end cards offer dual DVI outputs for use with two or more digital displays, while maintaining analog compatibility by bundling DVI-VGA converter dongles with the cards. Modern first person shooters like F.E.A.R. have fairly high system requirements that require a computer with a competent graphics card, enough RAM, and a fast enough CPU.

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