Accelerated Graphics Port Interface Specification

AGP3.0 Interface Specification

Rev. 1.0

Finally, Appendix C contains a glossary of terms used throughout this document.

1.2 Reference Documents

The following documents should be used as supporting reference material:

1. Accelerated Graphics Port Interface Specification, V2.0

2. AGP System Design Guide, V1.5

3. PCI Local Bus Specification, V2.2

1.3 Need for AGP3.0

In the past, AGP bandwidth has been scaled up at regular intervals. AGP1X and 2X were introduced

simultaneously, and AGP2.0 was introduced two years later. Now, AGP3.0 is recognized as the natural

progression beyond AGP2.0. It is expected to satisfy the bandwidth demands on the graphics interface

for at least two generations.

The need to increase bandwidth beyond AGP2.0 is based on the following trends:

• Workload content and real-time performance expectations are continuing to scale at a significant

rate every year. These are measured by the complexity of the scene being visualized and the

real-time scene changes and inter-activity that is expected.

• The capabilities of graphics sub-systems to render complex images are scaling at a tremendous

rate due to significant architectural and technological improvements.

• The host platform’s capabilities to support the graphics subsystem and workload requirements

are also continually increasing. These capabilities include processor speeds, system memory

capacity and bandwidth, and multiprocessing.

1.4 Evolutionary Aspects of AGP3.0

In this document, AGP1X, AGP2X, and AGP2.0 interfaces, as defined in the Accelerated Graphics Port

Interface Specification Revision 2.0, will be referred to as “AGP” or “AGP interfaces.” AGP3.0 is the next

step in the evolution of AGP2.0. This evolutionary interface maintains the same connector and, except

for a few additional signals to support the new signaling scheme, the same interface signals as AGP.

However, since the electrical signaling and clock rates are significantly different between AGP and

AGP3.0, compatibility at the platform level is achieved using a “Universal” motherboard. A Universal

motherboard is one that supports both AGP2.0 and AGP3.0 signaling. Chapter 2 describes this concept

in greater detail.

/ NOTE

Table 2 lists the AGP features that are unchanged in AGP3.0.