Hardware Reference
In-Depth Information
memory on the video card or the memory borrowed from the system performs the same
tasks.
The amount of video memory determines the maximum screen resolution and color depth
the device can support, among other features. You often can select how much memory
youwantonaparticular videoadapter; forexample, cardswithanywherefrom512MBto
4GB of video memory are common choices today. Although having more video memory
is not guaranteed to speed up your video adapter, it can increase the speed if it enables
a wider bus (for example, from 128 bits wide to 256 bits wide) or provides non-display
memory as a cache for commonly displayed objects. It also enables the card to generate
more colors and higher resolutions and allows 3D textures to be stored and processed on
the card, rather than in slower main memory.
Manytypesofmemoryhavebeenusedwithvideoadapters.Thesememorytypesaresum-
marized in
Table 12.6
.
Table 12.6 Memory Types Used in Video Display Adapters
Some of these, including FPM DRAM, EDO DRAM, and SDRAM, were also used for
main memory inPCs. All ofthe others were specifically designed foruse ingraphics sub-
systems.
