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How do I assign an IRQ to a Plug & Play Device?

Some, not many, Plug & Pray devices let you pick a different IRQ from the Device Manager. Uncheck "Automatic Setting" under resources for that device and then try to set the IRQ. My 3Com Ethernet card won't do this. But, my Winmodem will. It depends on the manufacturer of the device. If you ever check "Automatic Setting" then it will decide for you again.

If you can't do the above, then there are some tricks!
I like how Adam put it best:

"Each BIOS is a little different but in general you can't assign the PCI IRQ directly in plug-n-play. It's one of the reasons that the nickname Plug-n-Pray is appropriate.

You can do the effect of "shake the box and see if the contents settle in a more pleasing manner" by swapping the order of PCI cards.

Sometimes you can go into the P&Pray configuration page and set an IRQ number to "Legacy" which will force a PCI card to move (possible shoving other IRQs about or getting shared). You can then reboot and go back to the P&Pray of the BIOS and revert that IRQ to "Plug-n-Play" mode to release it. I was able to once move a Winmodem IRQ using this technique by removing the card, blocking the IRQ I wanted, then freeing that IRQ and then inserting the card." ( Adam Zilinskas, SolutionsIQ, aez at

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