What is the AGP

Intro

In 1997, Intel designed a specialized interface and connector to escape dependency to the PCI bus, considered as too slow to meet the requirements of high-speed display as graphics cards were becoming increasingly powerful.

The AGP interface is based on PCI bus interface, but it helps accelerate the rate of display and fitting perfectly for 3D display. To achieve this, it opens a direct access channel between the video controller and RAM (32 bit wide and running at 66 MHz). The total output is 266 MB /s for AGP1x (an output twice as much of a PCI bus).

Several major developments were made, making it faster and faster.

The different AGP bus

1 x AGP: Bus 32-bit to 66 MHz with a maximum transfer rate of 266 Mb/s, obtained by doubling the frequency of 33 MHz PCI bus.
2 × AGP: Bus 32-bit to 66 MHz DDR allowing a maximum transfer rate of 533 Mb/s.
AGP 4 ×: Bus 32-bit to 66 MHz QDR allowing a maximum transfer rate of 1 066Mb/s (1 GB/s).
AGP 8 ×: Bus 32-bit to 66 MHz frequency eightfold allowing a maximum theoretical transfer rate of 2133 Mb/s (2 GB/s).


Today, the AGP bus is outdated and its successor, PCI Express 16x bus was already in its 2.0 development phase in early 2008