ACPI.sys' thread idles at 25% CPU usage

[Veltas]

My computer seems to idle at 25% processor usage.  I looked at task manager and it rather helpfully told me it was 'System', so I downloaded Process Explorer and had a look at the threads under system and the culprit was labelled as 'ACPI.sys+0x1af7c', showing a near-constant 25% CPU usage!  I've attached what I'm seeing.

The computer I'm using is listed under my Comp. Specs forum info as 'Main Computer MEGA-NUKE'.

I've had this computer for over half a year with no such trouble.  The only thing I can think of that I've changed just before I noticed the issue was upgrading my OS to SP1, and downloading a few other important updates.  I don't download any updates other than the ones listed as 'important' (exception is the Browser Choice Screen) as I've had bad experiences in the past with it, but I'm hoping Windows is better at handling updates currently.

Thanks in advance to anyone attempting to help me.

EDIT: As far as I can tell all my hardware is updated to the latest set of drivers provided by their manufacturers.  I've unplugged all non-critical devices (keeping mouse, keyboard and screen).

EDIT2: Ran a full scan with AVG Free to no avail.  My chipset drivers are fully updated.

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[Allan]

As a starting point I'd suggest running full scans with both your anti virus app AND MalwareBytes.

I'd also suggest checking for a bios update and a more current chipset driver.

[patio]

I suspect chipset driver...

[Veltas]

Thank you for the quick reply.

Is a BIOS update safe?  I've been warned against it.

I've run full scans with AVG Free (sorry, forgot to mention).

I'm afraid to say my chipset driver is fully updated.

I'm performing a full scan on C: my only HDD with fully updated MBAM.

[Allan]

I've performed literally dozens of bios updates over the years and never had a problem. Just follow the instructions. The biggest cause of problems is an interruption in the update (power outage, a user stops the update, etc). Can something bad happen? Sure, I suppose so. But I've never had any issues at all.

And it's my guess that if there is a bios update available, it will address your issue.

[Veltas]

It may be of use to know that I have an Asus P7P55D-E LX motherboard.

I've downloaded the latest BIOS version but I've yet to change anything.  According to the website my version number is higher than the version that first supported my CPU, so I'd rather not 'flash' it or whatever unless you feel it may help anyway.

EDIT: Okay, I'll do it as soon as MBAM's finished.

[Salmon Trout]

First suggestion upon seeing ACPI.SYS: ensure you're using the latest BIOS available for your motherboard. Else, reset current BIOS settings after noting current settings. If you're overclocking, stop.

[Veltas]

Scan just finished:

Code: [Select]

Malwarebytes Anti-Malware 1.60.1.1000
www.malwarebytes.org

Database version: v2012.04.04.06

Windows 7 Service Pack 1 x64 NTFS
Internet Explorer 9.0.8112.16421
Chris :: MEGANUKE [administrator]

04/04/2012 17:05:49
mbam-log-2012-04-04 (17-05-49).txt

Scan type: Full scan
Scan options enabled: Memory | Startup | Registry | File System | Heuristics/Extra | Heuristics/Shuriken | PUP | PUM
Scan options disabled: P2P
Objects scanned: 929975
Time elapsed: 1 hour(s), 36 minute(s), 40 second(s)

Memory Processes Detected: 0
(No malicious items detected)

Memory Modules Detected: 0
(No malicious items detected)

Registry Keys Detected: 0
(No malicious items detected)

Registry Values Detected: 0
(No malicious items detected)

Registry Data Items Detected: 0
(No malicious items detected)

Folders Detected: 0
(No malicious items detected)

Files Detected: 3
C:\masm32\topgun.exe (Trojan.Dropper.PGen) -> No action taken.
C:\ASPIRE6530G\Users\Chris\AppData\Roaming\.minecraft\Cart\Cartograph_G_Post_Processor.exe (Trojan.Agent.cn) -> Quarantined and deleted successfully.
C:\ASPIRE6530G\Windows.old\Users\Christopher\Documents\Old Documents (Extract only)\Personal\publish\tarsvx1002.exe (Adware.Onlinegames) -> Quarantined and deleted successfully.

(end)

C:\masm32\topgun.exe I'll vouch for, I removed the other two.  I get the impression that this search hasn't turned up any solutions to my problem but at least I'm clean.

I shall now procede to flash the ROM or whatever it's called, and then I'll try default settings (and no, I'm not O.C.ing).

[Veltas]

After updating the BIOS the problem continues to persist.

I shall now reset the BIOS to default settings.

[Allan]

Well, the good news is your computer didn't explode

[Veltas]

Well, the good news is your computer didn't explode

Yep, that's always desirable!

After defaulting my BIOS settings the problem is still the same as before.  Any other ideas on how I can approach this?

[Allan]

Let's try a selective startup.

Open msconfig and on the General tab choose "selective startup" (uncheck all three items) and reboot. Does the problem still occur? If not, start adding items back to msconfig one or two at a time, rebooting after each change, until the problem reappears and you'll have identified the offending process. This is clearly a time consuming procedure, but it is the best way to determine if some process loading with the system is the cause of your problem.

After you've isolated the cause, do not use msconfig to permanently disable the process. Instead, if it is a service go to START - RUN and type: services.msc (then press enter) and disable the service OR, if it a program, you can download & run a simple app such as Mike Lin's Startup Control Panel (http://www.mlin.net/StartupCPL.shtml) to enable, disable, or otherwise manage startup programs.

[Veltas]

Let's try a selective startup.

Open msconfig and on the General tab choose "selective startup" (uncheck all three items) and reboot. Does the problem still occur? If not, start adding items back to msconfig one or two at a time, rebooting after each change, until the problem reappears and you'll have identified the offending process. This is clearly a time consuming procedure, but it is the best way to determine if some process loading with the system is the cause of your problem.

After you've isolated the cause, do not use msconfig to permanently disable the process. Instead, if it is a service go to START - RUN and type: services.msc (then press enter) and disable the service OR, if it a program, you can download & run a simple app such as Mike Lin's Startup Control Panel (http://www.mlin.net/StartupCPL.shtml) to enable, disable, or otherwise manage startup programs.

I attempted the selective startup without the options, to no avail.  I've also tried the diagnostic startup on msconfig, and standard safe mode.  Everytime the issue continues.

[Allan]

Please look in device manager. Are there any yellow or red symbols?

And one other thing you can try. Please replace the battery on the motherboard.

[Veltas]

Please look in device manager. Are there any yellow or red symbols?

And one other thing you can try. Please replace the battery on the motherboard.

Looked in device manager, no special symbols, warnings or other.

I don't have a spare motherboard battery at hand, could I also test by removing the battery altogether?

[Allan]

No, this error can be caused by a weak battery. I'm not saying that's the cause, but it's a possibility. Removing it will make things worse. Please get a new one when you can and see if that helps. After you get the new battery, if the problem persists try resetting the bios to default again.

[Veltas]

I found a battery lying around and replaced it with that, and I also removed the new stick of RAM I bought not too long ago (I spotted a thread that suggested that fix the issue temporarily).

Apart from going back to good ol' 2001 and halving my RAM, I haven't done much in my favor, the issue still occurs.  I'm going to put my old battery and RAM back in for now, I'll try out a new battery another day.

Thanks for all the help anyway, is there anything else I can try in the meantime?

[Allan]

Nothing I can think of. Sorry.

There are a bunch of folks a lot better with hardware issues than I am. Let's hope one of them has a thought.

[Salmon Trout]

A quick Google for example "ACPI.sys high cpu" shows dozens of hits. ACPI.sys is crucial to the OS interface with the hardware and there are many things that can lead to this problem. Wake on Lan, interrupts, PCI devices, USB devices, just about anthing on the motherboard or connected to it. Not to mention corrupted Windows files.

[Veltas]

A quick Google for example "ACPI.sys high cpu" shows dozens of hits. ACPI.sys is crucial to the OS interface with the hardware and there are many things that can lead to this problem. Wake on Lan, interrupts, PCI devices, USB devices, just about anthing on the motherboard or connected to it. Not to mention corrupted Windows files.

Unfortunately, I've already googled for this and seen this.  I don't think it's a wake on lan thing (I followed their instructions to fix it to no avail).  It's not the interrupts sub-process on Process Explorer that's taking up CPU, and if it is interrupts I certainly don't know how to fix it.  All my devices are working on the latest drivers (to my knowledge).  There are no oddities in my Device Manager as far as I can tell.  I tried a system integrity check which decided that my system files were okay.

It seems that each result leads to a different solution, so may well all be different issues; perhaps different to mine.  I've tried following their solutions but it's not worked for the ones I found.

[Veltas]

If this is a hardware issue, it could be my motherboard, my hard drive, my processor, my graphics card or my power pack; because I've tested everything else and these are all system critical.

I don't know much about hardware, so I have no idea what out of that list could cause that problem.  If anyone knows a possible cause or any way I could troubleshoot for more info on the problem then please tell me.

All I know is that this problem could end up being very expensive to fix.

[patio]

You already ran MemTest ? ?

[Veltas]

I ran MemTest and also tried swapping my RAM for other RAM.  No RAM change fixed the issue.

[Veltas]

BEHOLD, I installed Win7 again onto another partition and the clean install resolved the issue.  So I suppose I'm right in assuming this means that the issue is definately software related (thank God) and I just need to track down the rogue driver or update that's caused the issue.

Thanks for all the help guys, when I figure it out and get everything back to normal I'll post details and mark as solved.

EDIT:
On second thoughts, the issue wasn't resolved when I tried Safe Mode (on the old OS, obviously Safe Mode works on the new install) so barring the possibility that system files are corrupted, the only other possibility is that an update has bugged one of the core system files.

[Veltas]

After slowly installing all my old drivers and updates, I can't find a single one that causes the issue to reoccur.  After uninstalling and reinstalling all these drivers on the old installation, I can't get the problem to stop.

I'm going to put the issue down to corrupt system files FNAR and leave it at that, I don't know what the problem was but a fresh install seems to be the fix, and I wish I'd tried it earlier.

[Veltas]

Ahhhhhh...... that's better.

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