Graphics Card

graphic cardgraphic cardA graphic card is used to display picture on monitor or other displays. The image consists of pixels and CPU has to process these pixels to display picture. CPUs can process without graphic cards but requires hell of a processing power. A graphic card takes this load off the CPU and performs processing itself.

Graphic Card Components

A graphic card mainly consists of:
  • GPU – graphing processing unit
  • RAMDAC – random access memory with analogue to digital converter
  • I/O – Input / Output
Graphic card is a PCB- printed circuit board. The components and a BIOS Chip are integrated on it. BIOS Chip contains graphic card's setting, I/O and memory operations.

Graphic Card GPU

The purpose of GPU is to create images. A GPU has many similarities to computer's CPU but its architecture is dedicated to image processing for display. Therefore it performs essential mathematical and geometric calculation for graphics rendering. A special programming is embedded for analyzing the binary data. For these purposes a GPU consists of more transistors than standard CPU. So it produces greater heat and placed under heat sink or fan.

RAMDAC

Random access memory connected to digital to analogue converter. GPU created images and other information is kept in RAM. The information consists of data about each pixel, color and pixel's location on screen. RAM contains the mage as soon as it is displayed on the screen. Video RAM has a very high speed and is dual port allowing reading and writing simultaneously. The image is transferred to DAC that converts it into an analogue signal if required.

Graphic Card - I / Os

Graphic card is connected to the motherboard through one of these three interfaces:
  • AGP – advanced graphics port
  • PCIe – peripheral component interconnect Express
  • PCI – peripheral component interconnect
Graphic card can be plugged in any one of the slots. AGP is the oldest and the slowest of three. Now it has been replaced with PCIe and PCI slots. The PCI slots are the newer and faster than others. But still mostly used are PCIe slots due to speed and cost. Besides the slots the graphic card contains: DVI Connector, VGA Connector, TV-out, S-Video, USB port, Video in, video out and connector for digital camera. DVI allows LCD connection while VGA for CRT support. Some graphic cards contain dual head capability that allows dual screen support.

Factors that affect the graphic card

Here are the factors that define a graphic card. One can buy the card considering these factors, which are available along with the card as its features.
  • Interface (AGP, PCIe or PCI)
  • Memory (clock rate, Bus size, bandwidth)
  • SPEED (RAMDAC, GPU Clock)
The performance of the graphic card is measured by it frame rate. Frame rate of graphic card is the number of full images displayed per second.

Availability

What card one should buy depends what task he/she wants to accomplish. For email, word or surfing, integrated graphics are enough. Graphic cards are essential for 2-D or 3-D graphics. Game crazy people or the big industries performing lots of 3-D graphic work require high-end graphic cards. The cost of a graphic card ranges from $70 and above $600. Graphic cards @$70-$150 are suitable for low graphics such as web surfing, office application or small games. Graphic cards @$200-$400 are the best for 2-D graphics. However certain 3-D applications are also applicable. Graphic cards @$600 and above are high-end graphic cards and allow all 3-D graphic capabilities.