====== AGP Compatibility ======

Downloaded from [[http://www.ertyu.org/~steven_nikkel/agpcompatibility.html|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.

  * an 8x device must be 0.8v,
  * a 4x device can be 1.5v or 0.8v,
  * a 2x or 1x device can be 3.3v or 1.5v.

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

  * AGP 1.0 and 2.0 devices using a 1.5v key, signal at 1.5v, while AGP 3.0 devices using the 1.5v key and signal at 0.8v.
  * AGP 3.0 devices must be tolerant of 1.5v signalling though, they won't necessarily work, but will not be destroyed if inserted into an AGP 1.0/2.0 slot.

^ 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 |

  * A universal slot has no key.
  * A universal card has both keys or an absence of pins in the key region.

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

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

{{.agp:agp3.3v.jpg}}\\ AGP 3.3v keyed graphics card

{{.agp:agpuniv.jpg}}\\ 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:agp_registration_tab.jpg}}\\ AGP Registration Tab

{{.agp:agppro_key.jpg}}\\ AGP Pro Slot

{{.agp:agp_connectors.jpg}}\\ AGP Connectors

[[http://www.agpforum.org/|AGP Forum]] - contains the AGP specifications