Reading the BOG, I found the recommendation to enable APIC when running e.g. Windows XP. However the following text confuses me, and even scares me a little: "Please note that if you have earlier installed Windows XP with ACPI enabled in the BIOS, Windows XP will no longer boot up if ACPI is disabled in the BIOS. You will need to reinstall Windows XP". Does this mean that-when I now enable APIC- I run the risk that I can not boot up anymore when I disable it later, for instance when there will be problems with sound etc. ? If so, does that also mean that I have to do a complete fresh install of Windows XP, complete with all my applications ?
Hello ton, When you install Windows XP, it will check if you have ACPI enabled. How Windows XP manages resources like interrupts depends on whether ACPI is enabled or not. So, if you install Windows XP with ACPI enabled, Windows will dynamically manage those resources using ACPI. But if you then disable ACPI in the BIOS, then Windows won't boot up properly. You can always go back and re-enable ACPI. But if you choose NOT to enable ACPI, then you have to reinstall Windows XP so that it can use the resources as assigned by the BIOS. Please note that you do NOT need a fresh install of Windows XP. A repair-install is more than enough. Your applications will work as usual. You just need to redownload those Windows XP updates. Hope that helps you some.
If your bios is up to date and unless it has a bad ACPI implementation I would leave it ENABLED all time.