AGP Video Cards are still considered the standard for video cards on the market today. Even though they do not offer all of the features that the PCI Express Video Cards have, they are big step up from PCI Video Cards. AGP video cards can be capable of over 4 times the data transfer speed over PCI. AGP improved its data transfer rate by enabling data to be transferred both during the rise and fall of its clock cycle.
AGP Video Cards use pipelining and sideband addressing to improve its overall speed. Pipelining is a way to improve performance by letting tasks overlap themselves (For instance: AGP makes multiple requests for information during bus or memory access and PCI makes one request and does not make another until the data has been transferred). Sideband addressing separates the address bus from the data bus, which allows the graphics controller to issue new AGP commands while the main address/data lines are still operating. These two features greatly improve the speed of this style video card.
There are three versions and four basic speeds of AGP Video Cards:
AGP 1.0- supports 1x and 2x speeds and has a 3.3v connector
AGP 2.0- this version is compatible with 1.0 but adds 4x and 1.5v support
APG 3.0-supports 4x and 8x speeds and is only compatible with the 4x version in 2.0
Name |
Voltage
(V) |
Introduced with… |
Clock Speed
MHz |
AGP 1x |
3.3 or 1.5 |
AGP 1.0 (at 3.3 V) |
66 |
AGP 2x |
3.3 or 1.5 |
AGP 1.0 (at 3.3 V) |
133 |
AGP 4x |
1.5 or 0.8 |
AGP 2.0 (at 1.5 V) |
266 |
AGP 8x |
0.8 |
AGP 3.0 |
533 |
There are three different types of AGP Graphics Card mechanical board connectors. The 3.3v (which usually has a notch at the front end), the 1.5v (which usually has a notch at the back end), and the universal AGP slot which supports multiple voltages (there are no notches so both style cards can fit in it). The AGP Video Card and the monitor are what determine the quality of a computer’s video display, so keep in mind that the newer versions are better for more advanced graphics.
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