Hardware Interrupts causing 25% - 30% CPU usage

Benny · 21 Feb 2010

Hi whs, thank you for your help so far.

I have run the cmd system scan under administrator and the integrity of the system is OK. I have run multiple virus checkers and I have mcafee as my main A-V tool. They have found no errors or virus. Its really puzzling, as the ACPI.sys is a thread within the process "system", I cannot access it because process explorer says it cannot find the thread in system.

When I run a game or application that is intensive the problem seems to disappear completely as I minimise the window to check process explorer. Therefore in addition I dont think I have a heat problem, especially since the computer has been running for 6 months. I have also reinstalled windows 7 with the upgrade option only. All files and settings were kept as originals. That didnt make any difference.

whs · 21 Feb 2010

Hmm, the situation gets desperate. One last idea (although a long shot). Set the "windows driver foundation" service to manual or disabled (from automatic). This bugger had given me a lot of unexplainable similar issues in the past. Maybe it helps - maybe not.

Benny · 21 Feb 2010

Hi, Okay I tried that and no luck. I guess I am staring down the barrel of a full backroll to vista then windows 7 re-upgrade, at least then I will be sure of whatever is causing the problem (virus or software) will have gone. If it isnt then logically it will be a hardware error although I dont see that to be honest and then I can take it to get it seen by professionals as at least it is still under warranty.

Thanks for your help.

whs · 22 Feb 2010

I guess we lost the battle. Sorry.

catrinisin · 05 Mar 2010

Hey Benny,

From reading through this entire thread, I think you should be focusing on one general area. The BIOS and the Chipset drivers that talk to the BIOS. The file, ACPI.sys, is a system driver that is used to facilitate the advanced power management features of the motherboard. There appears to be a conflict on your system between the BIOS and the driver layer of your system. Specifically, ACPI.sys.

Assuming you have already installed the latest chipset drivers from HP; The first thing I would do it go into your BIOS settings and disable any power management options you see. If in fact they are already disabled, then go ahead and enable them and use the default values. Try S3 if you have that option. You could even reset your BIOS to it's defaults and see if that helps too.

If all that doesn't help, you can try disabling the ACPI drivers from the Windows side. Go into Device Manager and expand the System Devices. Disable any items here that mention ACPI. Keep in mind that this may stop sleep mode from working.

Hope this helps,
Chris

Lardy · 23 Mar 2010

Here's how I solved my issue: I had exactly the same symptoms as the original poster. Everything had been fine up until a few days ago. Then I realised that something was slowing my system down. Ran Process Explorer and noticed the Hardware Interrupts smashing one core of my dual core processor, accounting for about 35% total CPU usage.

After some investigation I found that disabling the onboard NIC halved the CPU usage to around 17%. Didn't make sense and led me down the wrong path for a while. After trying pretty much everything mentioned in this post, I decided to reinstall the OS. The issue persisted post install, so I physically disconnected as much hardware as I could, leaving CPU, RAM, HDD, Mouse & Keyboard. Connecting one piece of hardware at a time the culprit was eventually found...

PCI Modem! (or maybe PCI slot)! Disabling the modem in Windows and removing the phone cable did not reduce the Hardware Interrupts. Only when the card was removed from the PCI slot did the Hardware Interrupts drop to 0. I don't actually use it any more for faxing, so I didn't bother putting it in another PCI slot to see if the issue persisted. Finally.

Hope this story helps someone.

whs · 23 Mar 2010

PCI Modem! (or maybe PCI slot)! Disabling the modem in Windows and removing the phone cable did not reduce the Hardware Interrupts. Only when the card was removed from the PCI slot did the Hardware Interrupts drop to 0. I don't actually use it any more for faxing, so I didn't bother putting it in another PCI slot to see if the issue persisted. Finally.

Lardi, thank you for reporting how you solved the problem. You are already the second person I saw having this problem with the PCI modem. The other person had it on a laptop and could not take it out but solved the problem some other way (I forgot).

saik0 · 16 Jan 2011

Hi,

I've had the same problem with ACPI.sys using as much as 60% on one core of my CPU. I'm using Windows 7 x64.
The problem occured only after I put the system on "sleep". After few hours the system spontaneously woke up and I noticed the high CPU usage.
I discovered that ACPI.sys+0x1af44 thread was responsible (using sysinternals ProcessExplorer).
Since it happened after waking up from sleep I went through Event Viewer to see what triggered the resume.
The result: "Wake Source: Device -Intel(R) ICH10 Family PCI Express Root Port 5 - 3A48"
Proceeded to device manager to see what was on that port and voila: "Realtek PCIe GBE Family Controller" was shown.

Next I disabled the option in Power Management for the device: "Allow this device to wake the computer"
Immediately the CPU usage went to normal (without restarting).

I'm using the latest NIC drivers.
Sadly I want to use the WOL feature so this is kind of a nuissance...
I'll contact the mobo manufact and explain the situation but I don't expect much :\

~

whs · 16 Jan 2011

Thanks for giving us your experience report. That might be very helpful for another "victim".

Rammstein · 27 Jan 2011

Hello! Sorry for my English!

I have similar problem: Process Explorer shows Interrupts (Hardware Interrupts) causing 20-35% CPU usage. But I can't find source of my problem, because it doesn't always happens. Sometimes the problem does not appear at all, but when starts, it will not stop until hybrid sleep or restart.
I don't know how to identify problematic hardware, because problem can start unexpectedly, without any specific reasons.

Today it startеd again. I tried to disable some hardware (e.g. Network adapter, IDE ATA/ATAPI controllers) but takes no effect.

Need your help! Thanks in advance.