Hardware Reference
In-Depth Information
AMD Athlon 64 Chipsets
The Athlon 64 processor required a new generation of chipsets, both to support its 64-bit processor
architecture and to allow for integration of the memory controller into the processor. (The memory
controller has traditionally been located in the North Bridge chip or equivalent.) As a consequence,
some vendors do not use the term
North Bridge
to refer to the chipset component that connects the
processor to AGP video.
AMD 8000 (8151) Chipset
The AMD 8000 was AMD's first chipset designed for the Athlon 64 and Opteron families. Its
architecture was substantially different from the North Bridge/South Bridge or hub-based
architectures we are familiar with from the chipsets designed to support Pentium II/III/4/Celeron and
AMD Athlon/Athlon XP/Duron processors.
The AMD-8000 chipset was often referred to as the
AMD-8151
because the AMD-8151 provided the
connection between the Athlon 64 or Opteron processor and the AGP video slot—the task usually
performed by the North Bridge or MCH hub in other chipsets. The name of the North Bridge or MCH
hub chip is usually applied to the chipset. However, AMD referred to the AMD-8151 chip as the
AGP Graphics Tunnel chip because its only task was to provide a high-speed connection to the AGP
slot on the motherboard. The other components of the AMD-8000 chipset included the AMD-8111
HyperTransport I/O hub (South Bridge) and the AMD-8131 PCI-X Tunnel chip.
Due to delays in the development of the AMD-8151 AGP Graphics Tunnel chip, most vendors
through late 2003 used the AMD-8111 HyperTransport I/O hub alone or along with the AMD-8131
PCI-X Tunnel chip to provide a mixture of PCI and PCI-X slots on motherboards optimized as
servers. Newer systems have incorporated the AMD-8151 chip to provide AGP video, but the AMD-
8000 chipset was used primarily as a workstation/server chipset instead of as a desktop chipset.
The AMD-8151 AGP Graphics tunnel has the following major features:
• Supports AGP 2.0/3.0 (AGP 1x-8x) graphics cards
• 16-bit up/down HyperTransport connection to the processor
• 8-bit up/down HyperTransport connection to downstream chips
Following are the AMD-8111 HyperTransport I/O hub (South Bridge) chip's major features:
• PCI 2.2-compliant PCI bus (32-bit, 33MHz) for up to eight devices
• AC'97 2.2 audio (six-channel)
• Six USB 1.1/2.0 ports (three controllers)
• Two ATA/IDE host adapters supporting up to ATA-133 speeds
• Real-time clock (RTC)
• LPC bus
• Integrated 10/100 Ethernet
• Eight-bit up/down HyperTransport connection to upstream chips
The AMD-8131 HyperTransport PCI-X tunnel chip's major features include these:
• Two PCI-X bridges (A and B) supporting up to five PCI bus masters each
• PCI-X transfer rates up to 133MHz
