What is a Graphics Card?

Graphics Card

The term is usually used to refer to a separate, dedicated expansion card that is plugged into a slot on the computer's motherboard, as opposed to a graphics controller integrated into the motherboard chipset.
HardwareA video card consists of a printed circuit board on which the components are mounted. These include:
Graphics processing unit (GPU)The GPU is a microprocessor dedicated to manipulating and rendering graphics according to the instructions received from the computer's operating system and the software being used. At their simplest level, GPUs include functions for manipulating two-dimensional graphics, such as blitting. Modern and more advanced GPUs also include functions for generating and manipulating three-dimensional graphics elements, rendering objects with shading, lighting, texture mapping and other visual effects.
Video memory
Unlike integrated video controllers, which usually share memory with the rest of the computer, most video cards have their own separate onboard memory, referred to as video RAM (VRAM). VRAM is used to store the display image, as well as textures, buffers (the Z-buffer necessary for rendering 3D graphics, for example) and other elements. VRAM typically runs at higher speeds than desktop RAM. For the most part, current Graphics Cards use GDDR3 or GDD4 whereas desktop RAM is still using DDR2.
Video BIOS
The video BIOS or firmware chip is a chip that contains the basic program that governs the video card's operations and provides the instructions that allow the computer and software to interface with the card.
Connects to:
Motherboard via one of
AGP
PCI Express
PCI
Display via one of
VGA connector
Digital Visual Interface
Composite video
Component Video

Common Manufacturers:
ATI
NVIDIA