PC Hardware in a Nutshell, 3rd Edition

Components

A video adapter comprises the following components:

Graphics processor

Rather than depending on the main system CPU to create each video frame, a graphics accelerator contains a graphics processor, which is optimized to perform in hardware low-level video functions such as transferring bitmaps, doing color and pattern fills, scaling fonts, sizing and positioning windows, and drawing lines, polygons, and other graphics primitives. An accelerated video adapter also requires much less data to be transferred between the system bus and the video adapter. For example, to draw a circle with a frame grabber, the system CPU must create a bitmap of that circle and transfer it to the frame grabber. Conversely, given only the center and radius of the circle, a graphics accelerator can render the circle directly.

Early accelerators were optimized for 2D graphics operations, which are still most important when running standard business and personal software such as word processors and web browsers. More recent accelerators, including all current models, provide 3D acceleration, which is primarily useful for playing 3D graphics-intensive games. Unfortunately, some recent 3D adapters, particularly nVIDIA models, are so heavily optimized for 3D that they provide mediocre 2D performance. We have several venerable Matrox video adapters, for example, that are useless for playing 3D games, but provide better 2D video quality than any current 3D accelerator.

Video memory

Video adapters ...