In a Dell Optiplex, as in a number of other systems, there is no means in the BIOS of assigning an IRQ to a PCI slot. In a Dell Optiplex, each available PCI slot appears to be hardwired to share an IRQ with a built in device. When the IRQ is changed for the PCI slot in an attempt to assign the IRQ, both the internal device's IRQ and the PCI slot's IRQ are changed at the same time to the new IRQ. The recommended method of resolving an IRQ conflict is to power down and move the PCI adapter to another slot. The IRQ will still be shared, but this time it may be shared with an internal device which does a better job of sharing the IRQ.