One of latest entrants to the alphabet soup of bus types is the Accelerated Graphics Port (AGP). As its name implies, AGP is intended as a bus for graphics cards. Although PCI is more than sufficient for most users needs, there are some shortcoming with high-end applications. The need for something like AGP arises from problems when creating 3D graphics, which use a “texture map” to get the necessary effects. The problem lies in the fact that most video cards deal with at most 8MB, but texture maps are reaching 10 or even 20 MB (probably more by the time you read this.)
Added to this memory limitation is the bandwidth required to transfer that amount of data quickly. To get real-time 3D graphics, you need far better throughput than loading a document into WordPerfect. Added to this fact is that there is just s single PCI bus, which makes it even more of a bottleneck.
In essence the AGP is high-speed path between system memory and the video controller. It is no longer necessary to store things like the texture maps in the system memory rather than in the limited space of the video card. Because data transfer across the AGP bus can be up to fourth times that on the PCI bus, AGP provides even better performance.