CertiGuide to A+ (Core Hardware)  9  Chapter 1000:  Multimedia       9  III  Video Cards

Video BIOS 1 RAMDAC

The area of the video card that stores all the information about the currently displayed image is called the frame buffer.

The frame buffer is made up of various types of RAM (discussed later). The advantage of having video memory integrated into the video card itself is that it can be designed and tuned for the specific task of displaying an image.

The more video memory contained on the video card, the larger the size of the frame buffer.

This will dictate the maximum screen resolution and color depth.

For example, a 1024x768 screen resolution in 32-bit True Color requires 3MB of video memory.

A 1600x1200 screen resolution in 32-bit True Color requires slightly more than 7MB of video memory.

You will notice that both of these values are just shy of the PC friendly 4MB and 8MB values that PC memory comes in. A video card that would support these settings would need 4MB or 8MB of video memory respectively. As you can see, almost a full megabyte of memory goes unused.

Video BIOS 1 RAMDAC