A special card that fits inside your computer and uses a dedicated processor chip to speed up the action of drawing lines and images on the screen. In a normal PC, the main processor chip has to carry out all the calculations to display a line on screen, all at the same time as looking after the keyboard, mouse, disk drive and memory. By adding a graphics accelerator card you can speed up the reaction time of graphics software such as Windows, CAD or paint programs, as the dedicated processor takes over the job of handling the graphics.
