Operating Systems => PC (32bit) => Windows XP (Oct 2001) => Topic started by: chrisNova777 on September 24, 2017, 05:35:48 PM

Title: some comments on windows XP + ACPI mode vs STANDARD mode
Post by: chrisNova777 on September 24, 2017, 05:35:48 PM

I simply cannot record MIDI in ACPI mode in Windows XP. The timing is horrible--a terrible, annoying quarter-note lag. I was thinking SP2 would fix the problem, but it did not.

Thanks Microsoft. I now have a perfectly good USB audio/MIDI interface (Tascam us-122) that can't perform the most basic of functions because of this unfixable problem. For the umpteenth time, I now have to re-install in Standard PC mode.

What are the disadvantages of installing in Standard PC mode? I've heard it causes instability. Does anyone else here have to run Win XP in Standard PC mode because of this problem?

All I know is this:

I have installed XP in ACPI mode countless times and have ALWAYS had the poor MIDI timing.

And I have installed in Standard PC mode countless times and have always had NO MIDI timing problems whatsoever.

I'd say that has nothing to do with latency or settings within Cubase.

The only reason I'd rather not install in Standard PC is because everybody says not to in Win XP. They say it's not necessary.

As to why they say this and how it relates to me, I have no clue

from rme regarding hammerfall cards

Under Windows XP Microsoft has significantly improved both interrupt handling and ACPI. In most cases the interrupts will not be sharing IRQ 9. Even when, problems like with the above mentioned simultaneous network transmission are no longer found. Furthermore XP operates more reliable and stable using the ACPI mode. Therefore changing to Standard-PC mode under Windows XP is not recommended.

The worst thing to do is to use Standard-PC mode with the latest generation of single CPU motherboards, having an advanced programmable interrupt controller (APIC.) These boards offer 24 interrupts under Windows XP in ACPI mode (else found on dual CPU boards only) - but only 15 when using Standard-PC mode!

Need to reinstall for Standard PC mode? You don't have to. Just select Standard PC as the driver, it'll reboot like 3 times, reinstalling all the drivers for your devices (make sure you got your driver disks ready), and you're done. Going back to APCI from Standard PC mode requires a reinstall.
Title: Re: some comments on windows XP + ACPI mode vs STANDARD mode
Post by: chrisNova777 on July 21, 2019, 10:42:19 PM

Title: How do I disable ACPI mode on Windows XP?
Post by: chrisNova777 on September 29, 2021, 04:39:41 AM

How do I disable ACPI mode on Windows XP?
Article #28268 Updated on Apr 27, 2007 at 12:00 AM
ACPI mode * for VERY Advanced users * only necessary if IRQ steps are unmanageable * will not likely help laptop computers *

* This step is recommended to be one of the LAST RESORT options to try since it drastically changes your system’s IRQ configuration. Current computers RARELY need this step done.

If you have all your device on IRQ 9, 10, or 11 and changing PCI slots doesn’t change this, or if you have devices on IRQs higher than 15 in Windows XP it’s because you are running in ACPI mode. This can cause problems due to sharing and IRQs the hardware doesn’t know how to handle. Here’s how you can switch back to the normal Win98-BIOS-controlled IRQs.

* This step is not recommended for DUAL PROCESSOR machines – disabling ACPI will disable dual-processor support.

* WARNING: YOU MUST HAVE ALL HARDWARE DRIVERS AVAILABLE AT RESTART. This will re-detect ALL your hardware, and any hardware drivers needed will be asked for. THERE IS A (slight) CHANCE THIS WILL RENDER YOUR SYSTEM UNBOOTABLE, do this at your own risk.

* If you have a USB mouse, you may need to find an old PS/2 (round connector) mouse. USB is one of the last devices detected in this process, and therefore your mouse pointer will be unusable for part of this process if it is USB.

To disable ACPI, you’ll need to change the system setting from ‘ACPI-PC’ to ‘Standard-PC’. Right-Click on My Computer -> Properties -> Hardware -> Device Manager -> Computer -> Advanced Configuration and Power Interface (ACPI) PC -> Driver -> Update Driver -> Install from a list or specific location -> Don’t Search.. -> Standard-PC.

Note that changing this means that all drivers of your hardware are re-installed (keep the driver disks available). Additionally, make sure that PNP OS INSTALLED in BIOS is set to NO (very important). Also note that disabling ACPI mode may cause your computer to not power off when you perform a Windows shutdown. Simply push the power button after performing a shutdown.

Reversing this step – re-enabling ACPI – can be as simple asrepeating this step and choosing ACPI-compliant PC instead of Standard. Again, this will require drivers to be reloaded.