Accelerated graphics port (agp) bus interface, Agp 4x bus – HP XU700 User Manual
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2 System Board
Memory Controller Hub (82850)
The MCH supports one Pentium 4 processor at an FSB frequency of 100MHz
using AGTL+ signalling. Refer to
for a description of the System bus.
Accelerated Graphics Port (AGP) Bus Interface
A controller for the Universal AGP (Accelerated Graphics Port) Pro slot is
integrated in the MCH. The AGP Bus interface is compatible with the
Accelerated Graphics Port Specification, Rev 2.0, operating at 133 MHz, and
supporting up to 1 GB/sec data transfer rates. The MCH supports only a
synchronous AGP interface, coupling to the System bus frequency.
AGP 4x Bus
The AGP bus is a dedicated bus for the graphics subsystem, which meets the
needs of high quality 3D graphics applications. It has a direct link to the
MCH.
The AGP bus is based upon a 66 MHz, 32-bit PCI bus architecture, to which
several signal groups have been added to provide AGP-specific control and
transfer mechanisms.
AGP specific transactions always use pipelining. This control mechanism
increases the bus efficiency for data transfer. Sideband Addressing (SBA)
may also be used by AGP transaction requests which further increases the
bus efficiency for data transfer. The supported modes are detailed below:
•
FRAME-based AGP. Only the PCI semantics are: 66 MHz, 32-bit, 1.5 V,
266 MB/s peak transfer rate.
•
AGP 1X with pipelining, sideband addressing can be added: uses 66 MHz,
32-bit, 1.5 V, increased bus efficiency, 266 MB/s peak transfer rate.
•
AGP 2X with pipelining, sideband addressing can be added: 66 MHz
double clocked, 32-bit, 1.5 V, 533 MB/s peak transfer rate.
•
AGP 4X with pipelining, sideband addressing can be added: 133 MHz
double clocked, 32-bit, 1.5 V, increased bus efficiency, 1066 MB/s peak
transfer rate