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General Description of IRQ Sharing in Windows

Q252420

"In Windows, some or all of the devices on your ACPI motherboard may be listed when you view the resources in Device Manager as using the same IRQ (IRQ 9) (to view the list of resources click either Resources by type , or Resources by connection on the View menu). You cannot change the IRQ setting because the setting is unavailable. This occurs because Windows takes advantage of the ACPI features of the motherboard, including advanced PCI sharing. IRQ 9 is used by the PCI bus for IRQ steering. This feature lets you add more devices without generating IRQ conflicts."