Information concerning ACPI may be found here:
If you are considering disabling ACPI support, please note the following:
- disabling ACPI on an existing installation may crash your system;
- consider protecting your valuable data - use a drive image/ghost backup application;
- any resulting increase in audio performance may be less than expected;
- ACPI issues typically cause problems only when your soundcard shares an IRQ with other PCI/AGP cards;
- before disabling ACPI, try moving your soundcard to another slot to see if that helps.