CertiGuide to A+ (Core Hardware)  9  Chapter 0001:  Power Supplies - System Board       9  X  Buses

Cache and Buses 1 XI  Expansion Buses

Originally the video card had to compete with other devices on the same bus, causing saturation. Intel designed an expansion bus structure as a slot (the slot is seen later in this chapter) known as the Accelerated Graphics Port (AGP).

AGP is a port and not a bus, because it cannot be expanded, AGP does have its own 'pipe' between the AGP and the CPU and the main system memory. And the bus speed is faster than the rest of the expansion bus. AGP was a hit with game players who needed the performance boost.

AGP design calls for a combination of on-board RAM on the video card, as well as borrowing some of the PCs main memory for some processing.

When the AGP card is not using the main memory, it is released for use by other applications.

When AGP was released it was available as both a 1X and 2X specification. Two years later Intel released a 4X APG standard. Currently in late draft format is the 8X AGP specification.

The physical slot for 8X remains the same, changing only in how signaling occurs.

Before concluding this chapter, there is one more bus to look at. That is the expansion bus, which we will examine next.

Cache and Buses 1 XI  Expansion Buses