Accelerated Graphics Port Interface Specification

AGP3.0 Interface Specification

Rev. 1.0

The AGP3.0 Specification does not preclude a universal motherboard or add-in card from supporting

3.3V. Refer to sections 4.3.4 - 4.3.6 and 4.3.8 of the AGP Specification, revision 2.0 for further details on

a Universal Motherboard implementation. Refer to the AGP2.0 Add-in Card ECN #53 for further details

on Universal Add-in card implementation.

Table 16: Graphics Card Options

Graphics Card Types Connector Type Description

AGP 3.3 V Card

3.3V Slot

Supports only AGP 3.3 V signaling. Available speeds 1x, 2x.

AGP 1.5 V Card

1.5V Slot

Supports only AGP 1.5 V signaling. Available speeds 1x, 2x,

4x.

UAGP Card Double Slotted Supports AGP 3.3 V and 1.5 V signaling. Available speeds

1x, 2x, 4x.

AGP3.0 Card

1.5V Slot

Supports only AGP3.0 signaling. Available speeds 8x, 4x.

Universal 1.5V AGP3.0 Card

1.5V Slot

Supports AGP 1.5 V and AGP3.0 signaling. Available speeds

1x, 2x, 4x, in AGP2.0 mode and 8x, 4x in AGP3.0 mode

Universal AGP3.0 Card Double Slotted Supports AGP 3.3V, 1.5V and AGP3.0 signaling. Available

speeds 1x, 2x, 4x in AGP2.0 mode and 8x, 4x in AGP3.0

mode. This includes 3.3V support for 1x and 2x speeds.

2.4.2.1 AGP3.0 Mode of Operation

The mode of operation for configurations with AGP3.0 or Universal AGP3.0 motherboards and AGP3.0

or Universal AGP3.0 Cards will be AGP3.0. This mode of operation will be selected automatically by

hardware during power-up reset and cannot be changed by software. AGP3.0 Mode implies the

following:

1. AGP3.0 electrical signaling scheme is used.

2. The speed of the interface is 8x or 4x.

3. All changes to AGP introduced in AGP3.0 will be enforced.

If selected by the hardware, the AGP3.0 Mode will be in effect even in a Legacy OS environment that

supports AGP. However, optional new features introduced in AGP3.0 may only be enabled with

appropriate changes to the OS and other software. The details of these changes are found in a

separate document. The registers that need to be programmed to use these features are described in

Appendix B.

The motherboard and Card use the MB_DET#, GC_DET#, and TYPEDET# pins to determine mode of

operation according to Table 17: