AGP stands for "Accelerated Graphics Port."
Accelerated Graphics Port (AGP) technology has been around since the 1990s. Designed specifically for graphics cards expansion and much faster than PCI slots, AGP remained the standard for graphics cards for years, and is only now being superceded by PCI Express slots. AGP has undergone several revisions over the years, giving it faster bus speeds and other additional capabilities not included in its original incarnation.
1x AGP
Transferring data at a rate of 266 megabytes (MB) per second and powered by 3.3 volts of power from the computer power supply, AGP 1x -- the oldest and also the original incarnation of the technology -- can produce 3D graphics on screen and for 3D gaming. Eventually, 1x AGP gave way to 2x AGP, which approximately doubled the data bus speed transfer rate.
2x AGP
This version of AGP transfers data at a rate of 533 MB per second and runs on 3.3 volts supplied to the slot by the computer's power supply unit (PSU). Its increased speed and performance allowed for complex architecture and 3D images in games and applications.
4x AGP
This still newer AGP, also known as AGP 2.0. increased the data transfer rate over older versions of the standard; the 4x version of AGP transfers data at a rate of 1.07 GB per second -- once again, an approximate doubling of the previous version's bus speed (2x). The first version of AGP to include a low-power consumption design, it uses 1.5 volts of power from the power supply.
8x AGP
The fastest version of the protocol as of 2011, 8x AGP -- also referred to as AGP 3.0 -- can transfer data at a maximum of 2.14 gigabytes (GB) per second. It runs off 0.8 volts of power supplied by the power supply. This version is backwards compatible with 4x AGP cards, as the keying remains identical in both versions for this purpose.
AGP Pro
Launched in 1998, AGP Pro slots offer larger slot size with more voltage pins, allowing for high-power 3D graphics cards. AGP Pro is fully backward-compatible all the way back to 1x AGP, meaning you can install just about any AGP card into an AGP Pro slot. This capability allowed for maximum flexibility in system building and deployment.
Tags: power supply, data rate, graphics cards, volts power, Accelerated Graphics