AGP Compatibility

Downloaded from Steven Nikkel.

Speed is always backwards compatible, for example, a 4x device must be able to run at 2x and 1x. The signalling voltage is the only incompatible part.

The connectors are keyed so that you can only use compatible equipment.

Motherboard Key(s) Speed(s) Voltage(s)
AGP 3.3v 3.3v 2x, 1x 3.3v
AGP 1.5v 1.5v 4x, 2x, 1x 1.5v
Universal AGP none 4x, 2x, 1x 3.3v, 1.5v
AGP 3.0 1.5v 8x, 4x 0.8v
Universal 1.5v AGP 3.0 1.5v 8x, 4x, 2x, 1x 1.5v, 0.8v
Universal AGP 3.0 none 8x, 4x, 2x, 1x 3.3v, 1.5v, 0.8v


Graphics Card Key(s) Speed(s) Voltage(s)
AGP 3.3v 3.3v 2x, 1x 3.3v
AGP 1.5v 1.5v 4x, 2x, 1x 1.5v
Universal AGP 3.3v, 1.5v 4x, 2x, 1x 3.3v, 1.5v
AGP 3.0 1.5v 8x, 4x 0.8v
Universal 1.5v AGP 3.0 1.5v 8x, 4x, 2x, 1x 1.5v, 0.8v
Universal AGP 3.0 3.3v, 1.5v 8x, 4x, 2x, 1x 3.3v, 1.5v, 0.8v

3.3v key as follows: [Backpanel] 21pins [KEY] 41pins

1.5v key as follows: [Backpanel] 41pins [KEY] 21pins

agp3.3v.jpg
AGP 3.3v keyed graphics card

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AGP Universal graphics card

AGP Pro

AGP Pro is a extention to the AGP connector on both sides to provide additional power to an AGP card. It comes in two flavors, AGP Pro110 provides for 50-110W of power and requires two adjacent PCI slots for cooling. AGP Pro50 provides for 20-50W of power and requires an adjacent PCI slot for cooling.

An AGP Pro card will not work in an AGP slot. An AGP card will work in an AGP Pro slot, however the card must have a registration tab.

agp_registration_tab.jpg
AGP Registration Tab

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AGP Pro Slot

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AGP Connectors

AGP Forum - contains the AGP specifications