and SLI and other functions. Graphics
What are your needs?
The first decision you must make is whether you need a graphics card for handling 3D images or whether you simply requiring 2D image rendering. For 2D requirements, just a cheap solution. In many cases, an integrated graphics solution sufficient for 2D applications.
But with 3D graphics performance of graphics cards, has a direct bearing on the frame rate and image quality of 3D programs and games. The differences between the low and high end cards can be substantial, both in cost and performance.
Rendering 3D graphics is like lighting a stage, both the geometry of the shapes in question and illustrates the need to be taken into account. Geometry of an image calculates the parts of an object that can and can not be seen, the position of the eye and its perspective. The lighting is a calculation of the direction of light sources, their intensities and the respective shadows that occur. The second part to presenting a 3D image is the reproduction of colors and textures to the surface of objects and modifies them according to light and other factors.
Most modern graphics cards include a small microchip called the Graphics Processing Unit (GPU), which provides the algorithms and memory to process complex images. They reduce the workload for the main CPU, and allow faster processing. Different graphics cards have different abilities in terms of processing power. They can make and refresh images up to 60 or more times per second, calculate shadows quickly, create image depth by rendering distant objects at low resolution, modify surface textures smooth and eliminate pixelation.
What Specifications to Consider
CPU clock speed
This impact on performance for GRU. The clock speed itself is not the decisive factor. It is rather the per-clock performance of the graphics processor, as indicated by the number of pixels it can process per clock cycle.
Memory Size
This is the memory used exclusively for graphics operations, and can be as much as 512 MB. The more demanding your graphics applications are, the better you will be served with more memory on your graphics card.
16-32M
64M
128M
256M
512M
640M and more
Memory bandwidth
One thing that can slow down 3D graphics performance is the speed with which the computer delivers information to the graphics processor. A higher bandwidth means a faster data transfer, resulting in faster rendering speeds.
Shader Model
DirectX Shader Models allows developers control over the appearance of an image, as is done on-screen, introducing visual effects like multi-layered shadows, reflection and fog.
Execution Level
This is a speed, an image can be done, or "painted". This rate is set in texels per second, the number of 3D pixels that can be painted per second. A
Vertices / triangles
Graphics chips do not work with curves, but they are dealing with flat surfaces. A curve is created by more permanent plans designed to resemble a curve. 3D objects are created with multiple triangular surfaces, sometimes hundreds or even thousands, tessellated to represent the curves and angles in the real world. 3D artists dealing with the number of polygons required to form a shape. There are two different types of specification: vertices per second (i.e. angles in triangles), and triangles per second. To compare one measure with the others, you have to take into account that adjacent triangles share vertices.
Anti-aliasing
A technique used to smooth images by reducing the jagged increased effect caused by diagonal lines and square pixels. Different levels of anti-aliasing have different effects on performance.
RAMDAC
Random Access Memory Digital to Analogue Converter takes the image data and converts it into a format that your screen can use. A faster RAMDAC means that the graphics card can support higher output resolutions. Some cards have multiple RAMDAC allows the card to support multiple monitors.
TV-out
Some graphics card allows you to connect a television via either a composite (RCA) or S-Video connector. TV-Out
S-Video Out
S-video In and S-video out (VIVO)
YPbPr Connection for HDTV
DVI
Some graphics cards include a connector for DVI monitors, handy because a lot of LCD screens support DVI. DVI gives better picture quality than standard VGA connector.
Dual-head
Dual-head is a term used when two monitors are used side by side, stretching the desktop across both.
SLI (Scalable Link Interface).
With SLI you can couple two graphics cards in your computer so that each card to take half the rendering thereby doubling the performance.
When considering your graphics card, it pays to think about how much you need your computer to process your graphics output. Using a high-end graphics card with a high pixels per clock rating, large memory, fast processor and other features mean you can run the latest games efficiently, or work in intensive graphics development.
Different models
While there are many vendors of graphics cards, there are really only two major manufacturers of chips for graphics cards. Almost all graphics cards on the market are equipped with a chip manufactured by either ATI or Nvidia. With the same graphics chip will perform roughly the same as everyone else. But even if they use the same chip, some have slightly higher clock speeds, as well as manufacturer guaranteed overclocking-an even higher clock speed than that specified. Other factors that will influence your decision should include the amount of memory a card has (128 MB, 256 MB, 512 MB) and additional features such as TV-Out and dual-screen support.
