Reference Guide

1567
Audio hardware (sound cards) and drivers
Beginner’s guide to Cakewalk software
IRQs
An IRQ (Interrupt Request) is an assigned location where the CPU expects to be interrupted by a
device when it has completed a task. There are 16 IRQs on a computer. Usually, three or four are
taken by the system, leaving 12 or 13 for other devices, like printers, USB devices, hard disks, floppy
disk drives, keyboard and sound card. Some of these devices can share an IRQ with other devices,
but for the most part this is not a good thing, and for a sound card which can use a lot of CPU power,
it can be a real problem. IRQ conflicts can cause your system to freeze or fail to boot up properly, or
the system may fail to recognize your sound card. Sometimes the problem only reveals itself when
you attempt to use the device that is sharing an IRQ.
IRQ conflicts
Newer motherboards often use something called ACPI (Advanced Configuration and Power
Interface) which controls IRQ settings, in effect overriding the motherboard IRQ settings. ACPI, just
like Plug and Play, can sometimes lead to shared IRQs and problems with your sound card.
Checking for ACPI on Your System:
1. Look at your IRQ settings.
2. Look for an entry that says ACPI.
Resolving IRQ conflicts on a Non-ACPI system
The easiest way to resolve a conflict may be to remove the piece of hardware that is conflicting with
your sound card. Of course, this is not always possible, but if you have a modem, network card, or
some other hardware device that you do not use, removing it (and its driver) may free up an IRQ for
your sound card.
Sometimes you can change a sound card’s IRQ setting by physically moving the card to another
PCI/ISA slot, or by moving several hardware devices to new slots. To do this, uninstall the hardware
you want to move, along with its driver, put the hardware devices in their new slots and reinstall their
drivers. Once you have completed this, check the IRQ settings again.
If moving or removing hardware did not help, you may be able to use the system BIOS to change an
IRQ setting. To see if your BIOS allows you to make changes to your systems IRQ settings, consult
your motherboard’s documentation.