display adapter

The plug-in card (AGP, PCI or PCI Express) in a desktop computer that creates the electronic signals required by the monitor. It determines the maximum resolution, refresh rate and number of colors that can be displayed, which the monitor must also be able to support. On many PC motherboards, the display circuits are built into the chipset, and a card is not required.

The Graphics Pipeline

The display adapter's primary purpose is to continuously convert the graphic patterns (bitmaps) in memory frame buffers into signals for the monitor's screen. However, high-end adapters do a whole lot more. They move the image through a graphics pipeline adding texture and 2D and 3D effects, all functions that used to be done by the computer's CPU. A super fast gaming adapter is a sophisticated parallel processing computer (see graphics accelerator and graphics pipeline).

Analog and Digital Outputs

The first PC display adapters (CGA, EGA, PGA) sent digital signals to the monitor, which converted them into analog for the CRT. Starting with VGA, analog signals were output to the monitor. Increasingly, display adapters provide both analog and digital outputs, the latter a DVI interface for a flat panel monitor. On portables with LCD screens, the display circuitry has been digital from end to end. See shared video memory, graphics accelerator and how to select a PC monitor.

Call It a What?

Take your pick... graphics adapter, graphics board, graphics card, graphics controller, video display adapter, video display board, video display card, video display controller, video adapter, video board, video card, video controller, display board, display card, display controller, VGA adapter, VGA board, VGA card and VGA controller are other terms for the display adapter.

By the way, a "video graphics board" may refer to a regular display adapter or to a combo display adapter and video capture board that accepts analog NTSC video (see VIVO).

Screen Resolutions

These are the common screen resolutions that display adapters generate. There are higher resolutions for special applications, such as document imaging. The higher the resolution, the more information (pixels) can be displayed on screen at one time.

The World's Largest

Visitors used to explore this ceiling-high combination display adapter and sound card at The Computer Museum in Boston. (Image by FAYFOTO/Keith Quenzel; courtesy of The Computer History Museum, www.computerhistory.org.)

A Bit More Practical

Although display circuitry is built into many motherboards, plugging in a high-quality adapter such as this one, based on NVIDIA chips, is still required for the fastest rendering of animation and full-motion video. (Image courtesy of NVIDIA Corporation)

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