| The is a vital performance component of your | | | | rendered on screen, introducing visual effects like |
| computer, particularly if you play 3D games, or work | | | | multi-layered shadows, reflection and fog.Fill rateThis is |
| with graphics and video content. The graphics card sits | | | | the speed at an image can be rendered or "painted". |
| in an expansion card slot in your PC and it is | | | | This rate is specified in texels per second, the number |
| specifically designed to process image data and output | | | | of 3D pixels that can be painted per second. A texel is |
| it to your monitor, enabling you to see it. A graphics | | | | a pixel with depth (3D). The fill rate comes from the |
| card works by calculating how images appear, | | | | combined performance of the clock speed of the |
| particularly 3D images, and renders them to the screen. | | | | processor and the number of pixels it can process per |
| 3D images and video images take a lot of processing | | | | clock cycle, and will tell you how quickly an image can |
| capacity, and many graphics processors are complex, | | | | be fully rendered on screen.Vertices/trianglesGraphics |
| require fans to cool them and need direct power | | | | chips don't work on curves, rather they process flat |
| supply. The graphics card consists of a graphics | | | | surfaces. A curve is created by multiple flat planes |
| processor, a memory chip for graphics operations, and | | | | arranged to look like a curve. 3D objects are created |
| a RAMDAC for display output. It may also include | | | | with multiple triangular surfaces, sometimes hundreds |
| video capture, TV output and SLI and other functions. | | | | or even thousands, tessellated to represent the curves |
| You can find the graphics card that suits you by | | | | and angles of the real world. 3D artists are concerned |
| comparing specification between brands and vendors | | | | with the number of polygons required to form a shape. |
| on auAt au you can compare a great range of | | | | There are two different types of specification: vertices |
| appliances, and assess them according to their | | | | per second (I.e., angles the triangles), and triangles per |
| specifications, brands, prices and vendors.What are | | | | second. To compare one measure with the other, you |
| your needs?The first decision you need to make is | | | | have to take into account the fact that adjacent |
| whether you need a graphics card for handling 3D | | | | triangles share vertices.Anti-aliasingA technique used to |
| images or whether you are simply requiring 2D image | | | | smooth images by reducing the jagged stepping effect |
| rendering. For 2D requirements, you need only a | | | | caused by diagonal lines and square pixels. Different |
| low-cost solution. In many cases, an integrated | | | | levels of anti-aliasing have different effects on |
| graphics solution will suffice for 2D | | | | performance.RAMDACThe Random Access Memory |
| applications.However with 3D graphics, the | | | | Digital to Analogue Converter takes the image data |
| performance of the graphics card will impact directly | | | | and converts it to a format that your screen can use. |
| on the frame rate and image quality of 3D programs | | | | A faster RAMDAC means that the graphics card can |
| and games. The differences between the low and | | | | support higher output resolutions. Some cards have |
| high-end cards can be substantial, both in cost and | | | | multiple RAMDACs allowing that card to support |
| performance.Rendering 3D graphics is like lighting a | | | | multiple displays.TV-outSome graphics cards provide |
| stage, both the geometry of the shapes in question | | | | the option to connect a television via either a |
| and the lighting of it need to be taken into account. The | | | | composite (RCA) or S-Video connector.DVISome |
| geometry of an image calculates the parts of an | | | | graphics cards include a connector for DVI monitors, |
| object that can and can't be seen, the position of the | | | | handy because a lot of LCD screens support DVI. DVI |
| eye and its perspective. The lighting is a calculation of | | | | offers better image quality than the standard VGA |
| the direction of the light sources, their intensities and | | | | connector.Dual-headDual-head is a term used when |
| the respective shadows that occur. The second part | | | | two monitors are used side by side, stretching your |
| to presenting a 3D image is the rendering of colours | | | | desktop across both.SLI (Scalable Link Interface.)With |
| and textures to the surfaces of the objects, and | | | | SLI you can couple two graphics cards in your |
| modifying them according to light and other | | | | computer, enabling each card to take half the |
| factors.Most modern graphics cards include a small | | | | rendering thereby doubling the performance.When |
| microchip called the Graphics Processing Unit (GPU), | | | | considering your graphics card, it pays to think about |
| which are provide the algorithms and memory to | | | | how much you need your computer to process your |
| process complex images. They reduce the workload | | | | graphics output. Using a high end graphics card with a |
| of the main CPU, and provide faster processing. | | | | high pixels per clock rating, large memory, fast |
| Different graphics cards have different capabilities in | | | | processor and other features means that you can run |
| terms of processing power. They can render and | | | | the latest games efficiently, or work in intensive |
| refresh images up to 60 or more times per second, | | | | graphics development.Different ModelsWhile there are |
| calculate shadows quickly, create image depth by | | | | many vendors of graphics cards, there are actually |
| rendering distant objects at low resolution, modify | | | | only two major manufacturers of chips for graphics |
| surface textures fluidly and eliminate pixelation.What | | | | cards. Nearly every graphics card on the market |
| Specifications to ConsiderProcessor clock speedThis | | | | features a chip manufactured by either ATI or Nvidia. |
| impacts on the rendering capability of the GRU. The | | | | Cards using the same graphics chip will perform |
| clock speed itself is not the critical factor. Rather it is | | | | roughly the same as each other. However, even |
| the per-clock performance of the graphics processor, | | | | though they use the same chip, some feature slightly |
| which is indicated by the number of pixels it can | | | | higher clock speeds, as well as manufacturer |
| process per clock cycle.Memory sizeThis is the | | | | guaranteed overclocking-an even higher clock speed |
| memory capacity that is used exclusively for graphics | | | | than that specified. Other factors that will influence |
| operations, and can be as much as 512MB. The more | | | | your decision should include the amount of memory a |
| demanding your graphics applications are, the better | | | | card has (128MB, 256MB, 512MB) and its additional |
| you will be served with more memory on your | | | | features, such as TV-Out and dual-screen support.Use |
| graphics card.One thing that can slow down 3D | | | | the search facilities at au to compare the features, |
| graphics performance is the speed at which the | | | | prices and vendors of graphics cards.Andrew Gates |
| computer delivers information to the graphics | | | | for comparison online shopping service au. au helps |
| processor. A higher bandwidth means a faster data | | | | you compare the different graphics card from |
| transfer, resulting in faster rendering speeds.Shader | | | | different brands in terms of specifications and |
| modelDirectX Shader Models allows developers | | | | accessories. |
| control over the appearance of an image as it is | | | | |