Minimum Memory Requirements for Common Display Resolutions
Screen Resolution	8-Bit (256 color)	16-Bit (65-KB color)	24-Bit (16.7 Million Color)
640 x 480	512 KB	1 MB	1 MB
800 x 600	512 KB	1 MB	2 MB
1024 x 768	1 MB	2 MB	4 MB
1280 x 1024	2 MB	4 MB	4 MB
1600 x 1200	2 MB	4 MB	6 MB

Text-based adapters under MS-DOS don't need software drivers to interface between the operating system and the image on the screen. Windows, OS/2, and other graphics-rich environments do need drivers. In addition, controls are needed to adjust the refresh rate, resolution, and any special features the card offers. These needs are handled by the use of display drivers, a software layer that marries the card and monitor to the operating environment.

When installing a new card or operating system for a client, be sure to check the manufacturer's Web site for the latest display drivers. Not only will you reduce the likelihood of problems in using the new addition, but you will find that most new cards incorporate setup routines that can make quick work of getting a new display running.

Lesson Summary

The following points summarize the main elements of this lesson:

• Display adapters have gone through significant changes since the first PCs entered the marketplace.

• SVGA is considered the standard for applications today. The increasing use of graphical operating systems fueled the need for bigger monitors, higher resolution, and more colors.

• The coprocessor is a key factor in graphics-adapter performance.

• 24-bit cards are required to offer photorealistic color displays.

• Memory is a limiting factor in resolution and color depth.

• Drivers are the link between the display hardware and the operating system.

• The type and amount of memory have direct impact on video performance. Less memory means fewer colors, and slower memory types mean poorer performance.