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.

PC Mechanic's video cards page
Explains what a video card is and describes the different types of video standards.