HP XU700 - Manual (Page 56)

56
2 System Board
System Bus
System Bus
The system bus of the Pentium 4 processor is implemented in the GTL
(Gunning Transceiver Logic)+ technology. This technology features open-
drain signal drivers that are pulled up through resistors at bus extremities to
the operating voltage of the processor core. These resistors also act as bus
terminators, and are integrated in the processor and in the 82850 MCH.
The supported operating frequency of the GTL+ bus for the Pentium 4 is
100 MHz. The width of the data bus is 64 bits, while the width of the address
is 32 bits. Data bus transfers occur at four times the system bus, at 400 MHz.
Along with the operating frequencies, the processor voltage is set
automatically.
The control signals of the system bus allow the implementation of a “split -
transaction” bus protocol. This allows the Pentium 4 processor to send its
request (for example, for the contents of a given memory address) and then
to release the bus, rather than waiting for the result, thereby allowing it to
850
Memory
Controller Hub
(MCH)
82850
1.5V
AGP
PRO
Connector
I/O Controller Hub
(ICH) 82801AA
Dual Rambus Channel
Address (32)
Control
Data (64)
AGP 4x Bus
(133 MHz (1 GB/sec
data transfer rate)
Socket 423
100 MHz two-way System Bus
(Data Bus runs at 4 x 100 MHz,
3.2 GB/s transfer rate)
HUB LINK 8
(266 MB/s data
transfer rate)
3.2 GB/s at 400 MHz-
data transfer rate)
4 onboard RIMM sockets
supporting RDRAM memory.
Intel Pentium 4
Processor