Video Card / Graphics Card
A
video card (also called a
video adapter,
display card,
graphics card,
graphics board,
display adapter or
graphics adapter) is an
expansion card which generates a feed of output images to a display. Most video cards offer various functions such as accelerated rendering of
3D scenes and
2D graphics, MPEG-2/MPEG-4 decoding, TV output, or the ability to connect multiple monitors (
multi-monitor).
Video hardware can be integrated into the
motherboard or (as with more recent designs) the
CPU, but all modern motherboards (and some from the 1980s) provide expansion ports to which a video card can be connected.
[citation needed] In this configuration it is sometimes referred to as a
video controller or
graphics controller. Modern low-end to mid-range motherboards often include a graphics chipset manufactured by the developer of the
northbridge (e.g. an
AMD chipset with
Radeongraphics or an
Intel chipset with Intel graphics) on the motherboard. This graphics chip usually has a small quantity of embedded memory and takes some of the system's main RAM, reducing the total RAM available. This is usually called
integrated graphics or
on-board graphics, and is usually low in performance and undesirable for those wishing to run 3D applications. A dedicated graphics card on the other hand has its own Random Access Memory or
RAM and Processor specifically for processing video images, and thus offloads this work from the CPU and system RAM. Almost all of these motherboards allow (PCI-E) the disabling of the integrated graphics chip in
BIOS, and have an
AGP,
PCI, or
PCI Express(PCI-E) slot for adding a higher-performance graphics card in place of the integrated graphics.
Components
A modern video card consists of a
printed circuit board on which the components are mounted. These include:
[edit]Graphics Processing Unit
A
graphics processing unit (
GPU), also occasionally called
visual processing unit (
VPU), is a specialized
electronic circuit designed to rapidly manipulate and alter memory to accelerate the building of images in a
frame buffer intended for output to a display. A video card is also a computer unto itself.
[edit]Heat Sink
A
heat sink is mounted on high performance graphics cards. A heat sink spreads out the heat produced by the graphics processing unit evenly throughout the heat sink and unit itself. The heat sink commonly has a fan mounted as well to cool the heat sink and the graphics processing unit.
[edit]Video BIOS
The
video BIOS or
firmware contains a minimal program for initial set up and control of the video card. It may contain information on the memory timing, operating speeds and voltages of the graphics processor, RAM, and other details which can sometimes be changed. The usual reason for doing this is to
overclock the video card to allow faster video processing speeds, however, this has the potential to irreversibly damage the card with the possibility of cascaded damage to the motherboard.
The modern Video BIOS does NOT support all the functions of the video card, only sufficient to identify and initialize the card to display one of a few frame buffer or text display modes. It does not support, YUV to RGB translation, video scaling, pixel copying, compositing or any of the multitude of other 2D and 3D features of the video card.
Video memory
The memory capacity of most modern video cards ranges from 128 MB to 8 GB.[1][2] Since video memory needs to be accessed by the GPU and the display circuitry, it often uses special high-speed or multi-port memory, such as VRAM, WRAM, SGRAM, etc. Around 2003, the video memory was typically based on DDR technology. During and after that year, manufacturers moved towards DDR2, GDDR3, GDDR4 and GDDR5. The effective memory clock rate in modern cards is generally between 1 GHz and 6.3 GHz .
Video memory may be used for storing other data as well as the screen image, such as the
Z-buffer, which manages the depth coordinates in
3D graphics,
textures,
vertex buffers, and compiled shader programs.
High-Definition Multimedia Interface (HDMI)
An advanced digital audio/video interconnect released in 2003 and is commonly used to connect
game consoles and
DVD players to a display. HDMI supports copy protection through
HDCP.
