There are a variety of video standards that define the resolution and colors for displays. Support for a graphics standard is determined both by the monitor and by the video adapter. The monitor must be able to show the resolution and colors defined by the standard, and the video adapter must be capable of transmitting the appropriate signals to the monitor.
Listed here, in approximate order of increasing power and sophistication, are the more popular video standards for PCs. Note that many of these numbers represent only the minimums specified in the standards. Many suppliers of video adapters provide greater resolution and more colors.
VGA -- 640 x 480 resolution
SVGA -- 800 x 600 resolution
XGA -- 1024 x 768 resolution
SXGA -- 1280 x 1024 resolution
UXGA -- 1600 x 1200 resolution
PC Guide's video card reference In-depth reference information for video cards. Looks at how the video card works in detail and includes sections on: video memory, interfaces, resolution and color modes, refresh, display standards, 3D computing, and performance issues.