A graphics card or video card controls computer graphics output. During program execution, the processor calculates the data, it forwards it to the graphics card and it converts the data so that the monitor or projector can play everything as images.
Graphics cards are either a PC expansion cards (via the bus PCI, AGP or PCI Express, formerly ISA or VLB) connected to the motherboard or are included in the chipset on the motherboard.
Other modern high performance video cards are GPU video RAM RAMDAC and the connections for external devices (eg, for the monitor).
The graphics cards principle was first used in series production of the microcomputer Apple II, which was integrated on the motherboard. Graphics capabilities could be improved by addition to acquiring cards, (PAL color card, 80-column card).
The first IBM PC came in 1981 with a card on the market, which only allowed the monochrome appearance of text (MDA = Monochrome Display Adapter). The Hercules 1982 offered a much better card, the Hercules Graphics Card.
As of 1991, the graphics cards developed into independent small computers with their own GPU (Graphics Processing Unit) , a so-called Graphics or pixel engine, where you could not only set individual pixels, but which one commands for drawing lines and could send filling surfaces (Windows accelerator).
These functions accelerated mainly moving the window of the graphical user interface, hence the name.
The concept of additional functionality was always continued with time, for example, since 1995, functions for the acceleration of video playback (eg in AVI format) and decoding of compressed video data (eg, MPEG) were introduced. These functions were previously offered on separate cards.
The best-known hardware interface for graphics cards are PCI, AGP, and PCI Express. These interfaces are either buses or direct (AGP , PCI Express), which connect the bus controller with the graphics card.