Frequently Asked Questions

Q: How are the interrupts routed on the 4000832 motherboard?

A: For APIC mode, the motherboard interrupt architecture incorporates three Intel® APIC devices to manage and broadcast interrupts to local APICs in each processor. One of the APICs is located in the ICH3-S and the other two APICs are in the P64H2 (one for each PCI bus). The I/O APICs monitor each interrupt on each PCI device including PCI. When an interrupt occurs, a message corresponding to the interrupt is sent across the FSB processors.

The following table shows how the interrupts from the embedded devices and the PCI-X slots are connected.

 IRQ
Device
PCI Riser ConnectorPCI Riser Slot 1PCI Riser Slot 2PCI Riser Slot 3Other
ICH3IRQA    P64H2
IRQB    Video
IRQC    Promise ATA
IRQD     
IRQE     
IRQF     
IRQG     
IRQH     
IRQ14    Pri IDE
IRQ15     Sec IDE
SER IRQ    SIO
P64H2 Ch AIRQ0LP INTALP INTALP INTDLP INTC 
IRQ1LP INTCLP INTC  SCSI INTB
IRQ2LP INTDLP INTD  SCSI INTA
IRQ3LP INTBLP INTBLP INTALP INTD 
IRQ4LP TDO LP INTBLP INTA 
IRQ5LP TCK LP INTCLP INTB 
IRQ6     
IRQ7     
IRQ8     
IRQ9     
IRQ10     
IRQ11     
IRQ12     
IRQ13     
IRQ14     
IRQ15     
P64H2 Ch BIRQ1FL INTCFL INTC   
IRQ2FL INTDFL INTD   
IRQ3FL INTBFL INTBFL INTAFL INTD 
IRQ4FL TDO FL INTBFL INTA 
IRQ5FL TCK FL INTCFL INTB 
IRQ6    Gigabit Ch A
IRQ7    Gigabit Ch B
IRQ8     
IRQ9     
IRQ10     
IRQ11     
IRQ12     
IRQ13     
IRQ14     
IRQ15     

Note:
LP = Low Profile
FL = Full Length