A graphics card is an expansion card that operates in a slot of the motherboard and converts the information into visible and understandable characters, graphics and images. The graphics card essentially consists of one or two graphics processors with main memories, the graphics memory with the memory controller, the graphics card interface and one or more fans that dissipate the heat produced. The preferred graphics card interface is PCI Express or the AGP bus, Accelerated Graphics Port (AGP), via which the graphics card receives information and data from the motherboard.
The graphics card communicates with the processor, the main memory and the display. It is where images and graphic effects are processed and data is provided to the display. It determines the screen resolution and color depth set by graphics standards, as well as the processing speed. The Graphics Processing Unit( GPU) works independently of the central unit on the motherboard. Graphics are processed by converting individual picture elements into a pixel matrix, which is stored in the graphics memory at Graphics Double Data Rate( GDDR). The detail rendering for lighting effects and shadowing is handled by a vertex shader, and that for textures by a pixel shader. The shaders are small microprocessors that reside on the graphics card, or are part of the graphics processor. The display on the monitor screen is done by continuously repeating the pixel matrix. In order for the display to be continuous and flicker-free, a certain refresh rate is required.
Text display is basically the same as graphics display, it only differs in the form of the image. Whereby the text is stored as a character string in the image memory. Attributes are added to each character: Color, size, font, etc.
Historically, graphics cards have evolved from simple monochromatic cards, through plug-in cards with low color and graphics resolution, to the VGA format graphics card used for years and its many variants such as Super-VGA( SVGA), Extended Graphics Adapter(XGA), Ultra-XGA( UXGA), SUXGA. The VGA format and interface is an analogdisplay interface whose analog signals red, green and blue have been converted from the digital computer signals in a DA converter on the graphics card.
Graphics cards have a relatively high power consumption, which can be several hundred watts for extremely powerful graphics cards.