Video Card

Graphic Cards

A GeForce 6600 Series card by PNY
Connects to

Motherboard via one of:

Display via one of:

A video card (also called a video adapter, display card, graphics card, graphics board, display adapter or graphics adapter) is an 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. 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 Radeon graphics 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.


[edit] 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 frame buffer intended for output to a display.

[edit] Heat Sink

A graphics card heat sink with two fans from Arctic

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 firmware contains the basic program, which is usually hidden, that governs the video card’s operations and provides the instructions that allow the computer and software to interact with the card. It may contain information on the memory timing, operating speeds and voltages of the graphics processor, RAM, and other information. It is sometimes possible to change the BIOS (e.g. to enable factory-locked settings for higher performance), although this is typically only done by video card overclockers and has the potential to irreversibly damage the card.

[edit] Video memory

Type Memory clock rate (MHz) Bandwidth (GB/s)
DDR 166 – 950 1.2 – 3.04
DDR2 533 – 1000 8.5 – 16
GDDR3 700 – 2400 5.6 – 156.6
GDDR4 2000 – 3600 128 – 200
GDDR5 900 – 5700 130 – 230

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 vertex buffers, and compiled shader programs.

[edit] RAMDAC

The SCART etc.) only. These require a RAMDAC, but they reconvert the analog signal back to digital before they can display it, with the unavoidable loss of quality stemming from this digital-to-analog-to-digital conversion.

[edit] Outputs

Video In Video Out (VIVO) for S-Video (TV-out), Digital Visual Interface (DVI) for High-definition television (HDTV), and DB-15 for Video Graphics Array (VGA)

The most common connection systems between the video card and the computer display are:

[edit] Video Graphics Array (VGA) (DE-15)

Analog-based standard adopted in the late 1980s designed for CRT displays, also called VGA connector. Some problems of this standard are electrical noise, image distortion and sampling error evaluating pixels.

[edit] Digital Visual Interface (DVI)

Digital-based standard designed for displays such as flat-panel displays (native resolution. It is worth to note that most manufacturers include DVI-I connector, allowing(via simple adapter) standard RGB signal output to an old CRT or LCD monitor with VGA input.

[edit] Video In Video Out (VIVO) for S-Video, Composite video and Component video

9-pin mini-DIN connector, frequently used for VIVO connections.

Included to allow the connection with mini-DIN connector variations, and the VIVO splitter cable generally comes with either 4 connectors (S-Video in and out + composite video in and out), or 6 connectors (S-Video in and out + component PB out + component PR out + component Y out [also composite out] + composite in).

[edit] High-Definition Multimedia Interface (HDMI)

High-Definition Multimedia Interface (HDMI)

An advanced digital audio/video interconnect released in 2003 and is commonly used to connect HDCP.

[edit] DisplayPort


An advanced license- and royalty-free digital audio/video interconnect released in 2007. DisplayPort intends to replace VGA and DVI for connecting a display to a computer.

[edit] Other types of connection systems

Composite video Analog system with lower resolution; it uses the RCA connector.
Component video It has three cables, each with RCA connector (YPBPR for analog component); it is used in projectors, DVD players and some televisions.
DB13W3 An analog standard once used by IBM.
DMS-59 A connector that provides two DVI or VGA outputs on a single connector. This is a DMS-59 port.


[edit] Motherboard interface

Chronologically, connection systems between video card and motherboard were, mainly:

  • S-100 bus: designed in 1974 as a part of the Altair 8800, it was the first industry-standard bus for the microcomputer industry.
  • ISA: Introduced in 1981 by IBM, it became dominant in the marketplace in the 1980s. It was an 8 or 16-bit bus clocked at 8 MHz.
  • Macintosh II, it was a 32-bit bus with an average bandwidth of 10 to 20 MB/s.
  • MCA: Introduced in 1987 by IBM it was a 32-bit bus clocked at 10 MHz.
  • EISA: Released in 1988 to compete with IBM’s MCA, it was compatible with the earlier ISA bus. It was a 32-bit bus clocked at 8.33 MHz.
  • VLB: An extension of ISA, it was a 32-bit bus clocked at 33 MHz.
  • PCI: Replaced the EISA, ISA, MCA and VESA buses from 1993 onwards. PCI allowed dynamic connectivity between devices, avoiding the manual adjustments required with jumpers. It is a 32-bit bus clocked 33 MHz.
  • Sun Microsystems in 1995. It had a 64-bit bus clocked at 67 or 83 MHz.
  • toys, USB displays and display adapters exist.
  • AGP: First used in 1997, it is a dedicated-to-graphics bus. It is a 32-bit bus clocked at 66 MHz.
  • PCI-X: An extension of the PCI bus, it was introduced in 1998. It improves upon PCI by extending the width of bus to 64-bit and the clock frequency to up to 133 MHz.
  • PCI Express: Abbreviated PCIe, it is a point to point interface released in 2004. In 2006 provided double the data-transfer rate of AGP. It should not be confused with PCI-X, an enhanced version of the original PCI specification.

In the attached table[4] is a comparison between a selection of the features of some of those interfaces.

Bus Width (bits) Clock rate (MHz) Bandwidth (MB/s) Style
ISA XT 8 4.77 8 Parallel
ISA AT 16 8.33 16 Parallel
MCA 32 10 20 Parallel
NUBUS 32 10 10-40 Parallel
EISA 32 8.33 32 Parallel
VESA 32 40 160 Parallel
PCI 32 – 64 33 – 100 132 – 800 Parallel
AGP 1x 32 66 264 Parallel
AGP 2x 32 66 528 Parallel
AGP 4x 32 66 1000 Parallel
AGP 8x 32 66 2000 Parallel
PCIe x1 1 2500 / 5000 250 / 500 Serial
PCIe x4 1 × 4 2500 / 5000 1000 / 2000 Serial
PCIe x8 1 × 8 2500 / 5000 2000 / 4000 Serial
PCIe x16 1 × 16 2500 / 5000 4000 / 8000 Serial
PCIe x1 2.0 1 500 / 1000 Serial
PCIe x4 2.0 1 * 4 2000 / 4000 Serial
PCIe x8 2.0 1 * 8 4000 / 8000 Serial
PCIe x16 2.0 1 × 16 5000 / 10000 8000 / 16000 Serial
PCIe X1 3.0 1 1000 / 2000 Serial
PCIe X4 3.0 1 * 4 4000 / 8000 Serial
PCIe X8 3.0 1 * 8 8000 / 16000 Serial
PCIe X16 3.0 1 * 16 16000 / 32000 Serial

[edit] Power demand

As the processing power of video cards has increased, so has their demand for electrical power. Current high-performance video cards tend to consume a great deal of power. While CPU and [7] Modern video cards with a power consumption over 75 Watts usually include a combination of six-pin (75W) or eight-pin (150W) sockets that connect directly to the power supply.

[edit] Size

Video cards come in 2 sizes, to allow adding a videocard to even [9]

[edit] See also

[edit] References

  • Mueller, Scott (2005) Upgrading and Repairing PCs. 16th edition. Que Publishing. ISBN 0-7897-3173-8

[edit] External links

Source: Wikipedia