Steinberg's article about the ACPI problem.Read it

Question

Optimization of Windows 2000/XP: ACPI kills audio performance!

Optimization of Windows 2000/XP: ACPI kills audio performance!

If not indicated otherwise, this text refers to Windows 2000. Settings that should also be applied under Windows XP are stated additionally.

The main problem is the automatically chosen ACPI mode (*1) during installation. W2k will use only one IRQ (9) for all PCI devices. Normally this should be no problem, but in this case the IRQ sharing suffers from bad performance. The computer won't crash, and everything works, but not as well as it should. Two examples: When using a Hammerfall USB/MIDI operation will cause audio stuttering even at highest latency. Data transfers via a network card in the background will disturb audio playback significantly.

The remedy is to change from ACPI to Standard-PC mode. Here's how to do it:

Before installation of W2k:

Check BIOS: the entry Plug and Play OS in your mobo's BIOS should be set to 'NO'.

When installing W2k:

The mode Standard-PC can be selected already prior to a W2k installation. Hit F6 when you are asked for updated SCSI etc. device drivers (blue screen). Then press F5 and choose Standard-PC.

After installation:

Check BIOS: the entry Plug and Play OS in your mobo's BIOS should be set to 'NO'.
Go to Device Manager (Control Panel/System/Hardware), click on 'Computer', then double click on 'ACPI-PC'. Go on with 'Driver' and 'Update Driver'. Select 'Display a list of the known drivers for this device', then 'Show all hardware of this device class'. Now you can select 'Standard-PC' in the list shown in the right window.

Windows 2000 will re-start and re-install all hardware. After this the PC will use the BIOS' IRQ assignments. After the successful reorganization your device manager should look like this:

The assignment to Standard PC bears risks and is not recommended by Microsoft.
Eventually you will have to reinstall Windows and already select the Standard PC mode during the installation.
Further information you can find in the Microsoft knowledgebase (support.microsoft.com).

The ACPI problem is not as severe with Windows XP, as Microsoft has introduced a number of beneficial changes. However, it might still occur that ACPI mode has to be deactivated manually with some system configurations. The procedure here is in principle the same as with Windows 2000.

To find out how your IRQs are assigned, do the following:

Go to the Start menu and click on "Run". Now enter "msinfo32". This starts the system information program. On the left hand side you can see a 'tree' view, similar to those used in the Explorer. Click on the left on "Hardware Resources" and then on "IRQs". On the right hand side, there should appear a list of your devices with the respective IRQ to which it has been assigned. Check if devices (especially your audio card) share an IRQ with other devices, as with Windows 2000. If this is the case, then you should deactivate ACPI.

(*1) ACPI = Automatic Configuration Power Interface

This article is based on information that was kindly provided by RME. For further information regarding this issue please check out RME´s website:
http://www.rme-audio.com/english/index.htm

Whether or not you had to deaktivate ACPI, please read as well the article regarding the optimization of the processor scheduling in Win2K/XP:

http://service.steinberg.net/knowledge.nsf/show/optimize_processor_scheduling_win2k_xp
-------------------------------------------------------------end------------------------------------------------
Post Scriptum: Dear Dell engineers,
I have searched this information for you in order to inprove 8200's BIOS. If you go to http://www.tascam.com you'll find an article like this one. The same if you visit any other audio/midi software manufacturer.
I hope this helps!
Best Regards,
Miguel Angel.
SPAIN

thebithead · Answer

miguelafg wrote:
-

snip-snip

-
- The main problem is the automatically chosen ACPI
- mode (*1) during installation. W2k will use only one
- IRQ (9) for all PCI devices. Normally this should be
- no problem, but in this case the IRQ sharing suffers
- from bad performance.

I think it is hard to make a general statement like that. Sure there are circumstances where certain combinations of hardware can have performance problems sharing IRQs. Especially in desktop systems where people are allowed to upgrade the hardware in their systems, or when older hardware is used.

However, most modern ACPI systems should not suffer performance problems from IRQ sharing.

-tom

Inspiron 7500 & 8200.
for Inspiron 8200 FAQ, goto:
http://www.geocities.com/thebithead/I8200FAQ.htm

Rance485 · Answer

miguelafg:

See my response to your earlier post. You've recently made four posts to this board regarding the same problem. When you have additional information to add to a problem, please post a "reply" to your thread. Posting a new topic every time makes it difficult to follow your issue and will probably result in less helpful responses overall.

miguelafg · Answer

Dear Tom,
The truth is that once I took my Inspiron out of the box I installed Cubase VST 5.1 which is in fact compatible with XP. I pressed play and I could hear Cubase's metronome going sluggish and ramdomly interrupted. I mean, no extra hardware used, just the Crystal audio board. I admit that the Inspiron 8200 is the most powerfull notebook I ever tried, but, you know, I am a musician and audio engineer so I am really disapointed and worried about this matter.
By the way, Also I tried Sonic Foundry's Sound Forge 6.0 which has been wrote from scratch for Windows XP. Timing problems and glitches too.
Have you heard of Cubase SX? Yeah, coded for W XP too. The same as Cubase VST 5.1.

Not to say a word about my Tascam US-428 audio/midi USB interface. Painful.
I cannot even do what I could with a 386sx. Just sequencing a few midi tracks.

I do not know a word about computing, but I've heard that if Dell puts an option in BIOS to disable "OS P'N'P detecting" I could perform an " Standard PC" installation being able then to asign IRQ's manually.
Or maybe Microsoft would make a patch for theese models, who knows...
Thank you for your reply.
Best Regards,

Miguel

P. S. excuse my English. It's not my native language.

miguelafg · Answer

DELL-Rance wrote:
- miguelafg:
-
- See my response to your earlier post. You've
- recently made four posts to this board regarding the
- same problem. When you have additional information
- to add to a problem, please post a "reply" to your
- thread. Posting a new topic every time makes it
- difficult to follow your issue and will probably
- result in less helpful responses overall.
-
-
-
-
Sorry for that Rance. Thank you for your advice. I'm a newbie at forums.
I am just desperate and quite disapointed for not being able to use my computer for music purposes that is why I bought my i8200.
As my English is rather painful and as I do not want to generate some misunderstanding I decided not to post any more, but read only.
I'll just wait until it gets fixed itself.
Sorry again and thank you so much.
Best Regards,

Miguel.

bill.newell · Answer

Miguel,

I really think you need to spend more time reading through this forum's archives, as well as reading forums on pro audio web sites, and get a better understanding of how to tune a PC workstation for audio applications, before you make so many sweeping (and false) statements about what will work and what won't.

An internal audio card on a notebook PC, >any< notebook PC, isn't going to give you the low latency you're looking for. It won't have an ASIO- or DX8-compliant driver. A USB audio device such as the Tascam US-428 can do better, subject to the guidelines discussed elsewhere in this forum. A PCMCIA or 1394-based audio device can do better still, again subject to the guidelines discussed elsewhere.

As for the statements made in the Steinberg tech note you quoted, it is very true that disabling ACPI can improve your latency, although with Win2K and WinXP it isn't the changing of the IRQ assignments that gets you the improvements. To the extent that certain systems may have problems under Win2K with too many devices sharing one IRQ priority, it involves non-Intel mobo's and chipsets, and Dell is exclusively an Intel-based manufacturer. The Steinberg note reiterates what I've already tried to tell you, that under WinXP, the IRQ assignments can't possibly matter.

ACPI is an extremely valuable feature on a notebook PC. You have to decide whether you want to give it up in order to get a small incremental improvement in your latency. The stuttering behavior is a separate issue, and reinstallation of the OS on a clean disk, without all the extra junk on your system, will make a big difference there. I know you might think it should just plug in and work smoothly without any software configuration at all, but the simple truth is that the software is set up to best suit the needs of casual home users and gamers, and >not< to suit the special needs of pro audio or video applications. People can argue about that fact on here at length, and they already do :), but it won't change Dell's marketing priorities. My advice is to concentrate on the technical advice you've been given.

(bill)
--
I am a software engineer, not a musician.

Message Edited on 06/28/02 03:04PM by bill.newell

DeathRider · Answer

You might want to try running tweakui from Microsoft.

http://www.microsoft.com/windowsxp/pro/downloads/powertoys.asp

You can then disale all the eycandy, drive polling, ect. It might help your problem.

But be careful what you shut off.

--------------------------------------------------------------------------
i8200/1.6/(Sharp) UXGA/64MB GF4 440/256MB Dell/256MB Crucial/20GB/8xDVD/Actiontec MD56ORD, driver 3.5.32.2

i3500/PII366/14.1" XGA/256MB Crucial/20GB/2xDVD

My latest configs

thebithead · Answer

I don't know much about the Audio processing you are talking about. It could be that notebook computers are not designed for the types of applications that you are attempting to run. The audio hardware in a notebook is adequate for most people (it works fine for my needs), but you seem to have some specific high-end requirements. The audio hardware in notebooks is not something that can be changed. They are usually built-in on the motherboard so you are stuck with that.

For your adanced audio processing needs, you might be better off using a desktop computer, where you have the ability to change the audio hardware to some high-end equipment that can do what you want. Some tasks are just not well suited for notebook computers.

-tom

Inspiron 7500 & 8200.
for Inspiron 8200 FAQ, goto:
http://www.geocities.com/thebithead/I8200FAQ.htm

miguelafg · Answer

Dear Bill,
First of all thank you for your help and advice.

- I really think you need to spend more time reading
- through this forum's archives...
You're right. I just spent four hours a day for two weeks.

- An internal audio card on a notebook PC, >any<
- notebook PC, isn't going to give you the low latency
- you're looking for.
I do not need low latency at all nither do I want to use the internal audio board. I just unpacked my i8200, installed Cubase VST 5.1, pressed play and Cubase's metronome went sluggish and glitching as if it were interrupted by something.

A USB audio device such as
- the Tascam US-428 can do better, subject to the
- guidelines discussed elsewhere in this forum
I do own a Tascam US-428. It goes wrong too. I've read those articles too. So I'm affraid my i8200 came with some problem. Who knows, It travelled from Ireland to Spain.

- As for the statements made in the Steinberg tech
- note you quoted, it is very true that disabling ACPI
- can improve your latency...
I do not want to spend my time changing ACPI, IRQ or anything. I do not want to fix an unexisting problem. I just want to make music and sounds. I just want my i8200 going straight ahead ( clic, click, clilck, click) with no sgrange cut offs.

-Dell's marketing priorities...
I've managed my own business for fourteen years so I do think I know well any company's marketing priorities. S E L L.

- I am a musician, not a software engineer nither am I interested on hardware.

Thank you again.
Regards,
Miguel

miguelafg · Answer

Thank you for your advice. I've tried TweakUI from MS but it didn't work either. I'm affraid my i8200 came with some sort of problem from factory. Regards, Miguel

Philmar · Answer

hi, so I have the I8100 with ess sound card, it has its own and lone irq number 5 I use progs like NI´s B4 and the latency is about 40ms, same as on a desktop PC. how should these 40ms be decreased?

Philmar · Answer

well I think its rather a software or driver problem, try reinstalling, helped me with some music progs.

miguelafg · Answer

philmar wrote:
- hi, so I have the I8100 with ess sound card, it has
- its own and lone irq number 5
- I use progs like NI´s B4 and the latency is about
- 40ms, same as on a desktop PC.
- how should these 40ms be decreased?
-

That's the lowest latency you can achieve with ASIO and that soundcard.
You are lucky.
Just enjoy it.
Regards,

rpries · Answer

Dell is delivering misconfigured Laptops for the use of Audiosoftware. That's all about it. Ronny

rpries · Answer

Well,

irq sharing is a bottleneck. it works on most fields but not on audio. I'm sure that many people will try to tell the opposite, but it's the source of most clicks. The card on its own irq can work with lower latency than on systems without its own irq, isn't that a proof?

Ronny

WmBC · Answer

Something isn't right when a P4 powerhouse can't do what any Pentium 133mx could do. This is so far out of my field I have no suggestions, but it seems odd that with all the advances are machines are less versatile.

Locked Topics – Laptops General

Steinberg's article about the ACPI problem.Read it

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