HP Vectra XA 6/xxx HP Vectra VA 6/xxx and XA 6/xxx pc - technical reference ma - Page 25

2 System Board Devices on the Processor-Local Bus Chip-Set The Intel 82440 FX chip-set comprises three chips. Two are concerned with controlling memory accesses. These are the data bus accelerator (DBX) chip (SB82442FX) and the combined PL/PCI bridge and memory controller (PMC) chip (SB82441FX). The DBX chip, controlled by the PMC chip, implements a 64-bit data path (not interleaved) between the Processor-Local bus and main memory modules. Processor-Local Bus PCI Bus ISA Bus Pentium Pro Processor 82442FX Data Bus Accelerator (DBX) Host Interface Clocks and Misc. PMC Interface DRAM Interface Main Memory 82371SB PCI/ISA Bridge PCI Master PCI Slave ISA Bus Controller APIC IDE Controller BIOS DBX Interface Main Memory Clocks Controller and Misc. Host Interface PCI Interface 82441FX PL/PCI Bridge (PMC) The PCI/ISA Bridge chip (otherwise known as PIIX3, or as the system I/O chip, SIO-A) is an Intel SB82371SB. It is not only responsible for transferring data between the PCI bus and the ISA expansion bus, but also contains the IDE controller. 17