"ACPI Kills Audio Performance" - Optimizing Audio in Windows XP?

Joined
Mar 28, 2005
Messages
2,852
I came across this website when looking for a way to get rid of unexplained popping in my audio. It claims that the culprit is ACPI and that the problem can be corrected by changing your irg settings as explained below. Is any one familiar with this?? I followed the instructions and the pc rebooted and reinstalled all drivers. It seems faster and the audio sounds clearer for some reason.

After you read this you can read more about this here www.musicxp.net or searching for the the article entitled, "ACPI Kills Audio Performance by www.steinberg.net

This is the original site >>> http://www.thewhippinpost.co.uk/audio/optimise-pc-audio.htm

If you are an audio mod or just a sound guru please comment on this. I would to hear everyones opinions on this setup. Thanks - Aratech

Cubase SX - Optimizing XP and Windows 2000

Before trying the following, check your motherboard manual and the manufacturers details for your soundcard - Some soundcards don't recommend Standard PC.
ALSO, read the disclaimer (below)

If you're suffering from pops and clicks in your audio streams with no obvious explanation, then read on...

First look at the System Device Manager and check the IRQ's for all your devices. If they are the same (or many of them are) chances are ACPI is messing wid ya mind. If they're not, LEAVE WELL ALONE! Go no further.

Buying a PC with Windows 2000 or XP pre-installed will often mean that it's not optimally configured for music applications.

When Windows goes through its installation routine, by default, it sets itself up in ACPI (Advanced Configeration and Power Interface) mode.
This applies a variety of internal settings that can affect the performance of the machine when it's placed under the sort of strain that complex audio work can produce, in particular, an ACPI configured PC will generally route all IRQ assignments to just one IRQ, even if others are free!

Simply put, this'll mean that any hardware present on your machine - audio and graphics cards for example - may struggle for bandwidth across the PCI Buss on the motherboard (or, as someone in the film Full Metal Jacket quoted, It's "...like sucking a golfball through a hosepipe!").

When you start throwing complex GUI's and high-res screen redraws through the graphics card while still trying to shuffle 16 tracks of 24-bit/96khz audio around, these two processes can begin to steal resources and lead to graphics problems, audio glitching and popping - Cubase SX is particularly sensitive to this and it's likely that ACPI is the culprit!.

If this sounds sounds familiar, try this:

Open Control Panel
Go to Hardware Settings
Click the small '+' sign to the right of the computer entry
...if it says ACPI Advanced Uniprocessor PC - Chances are your audio and graphics card are sharing IRQ's...uh oh!

Windows XP users should

Right Click on ACPI
Select Update Drivers
Select from list
Select "Standard PC" (at the bottom)
Hit Apply.
Windows will now reboot and reinstall all of your hardware, assigning each item to an individual IRQ

Windows 2000 users, should not do it.

W2K doesn't like it and can't handle ACPI properly.
 

BBA

Supreme [H]ardness
Joined
Apr 25, 2003
Messages
5,382
Don't do this if you have a dual core CPU either, because the standard hal is single core/cpu only.

Also, this may require a repair of the OS by booting with the windows install CD and doing a repair installation.
 

Chastity

Gawd
Joined
Oct 23, 2005
Messages
593
An easy to see if you need to do this is to bring up teh Hardware Manager, and change the view to "Resources By Connection" and check your IRQ's.
 

GotNoRice

[H]F Junkie
Joined
Jul 11, 2001
Messages
10,893
My EMU 0404 shares an IRQ with one of my SCSI chanels (i'm only using one so no idea if it's on the active or idle channel). My Audigy 2 ZS shares an IRQ with one of my USB controllers. Beyond that things are pretty spread out. I havn't noticed any audio problems and i've never heard of this IRQ issue before. How big of a deal is this really?
 

AdamW

Limp Gawd
Joined
Dec 6, 2004
Messages
468
I think the guy who wrote that article is getting his ACPI and his APIC confused. In Linux, at least, you can disable APIC (which does IRQ routing) without disabling ACPI. I'd assume you can do the same on Windows.
 

BBA

Supreme [H]ardness
Joined
Apr 25, 2003
Messages
5,382
It's old school lame stuff.

All the old timers have been through this stuff and gave up...IRQ sharing is normal and good.
 

Mav451

Supreme [H]ardness
Joined
Jul 23, 2004
Messages
4,740
I still do this on my nForce2 since there's hissing & popping if I type while listening to music. This is whether it is streaming or from my own hard drive. Changing it from "Uniprocessor" to "Advanced Config & Power Interface PC" does the trick.

I'm wondering if I still have to do this on nF4 boards in the future...
 
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