AGP term explained

AGP - Accelerated Graphics Port

This interface designed by Intel allows the graphics card to access memory directly. This results in faster graphics performance.

The AGP slot has now replaced the PCI slot, which was used widely in the past for graphics cards.

The new advanced AGP slot offers different speeds for advanced graphics support.

The AGP slot ranges from 2x to 8x

The faster your AGP is, the faster your graphics card will run. For most games and applications 4x will run your programs easily. The new graphics cards, such as the 9800 pro are designed to utilize the extra bandwidth provided on the 8x AGP