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Windows 7: Hardware Interrupts causing 25% - 30% CPU usage

31 Jan 2011   #21

windows 7 64bit

Quote   Quote: Originally Posted by Rammstein View Post
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.
When you run process explorer do you see the CPU spending time in DPCs and Interrupts and the CPU having a steady ~30% usage ?

It could be your iPhone or some other USB device. I discovered yesterday that my iPhone was triggering this. The system is at near 0% CPU when idle but after I connect my iphone it jumps to 30% and stays there (doin somethin with DPCs and Interrupts) long after the iphone is gone. But after a reboot or a sleep, the system goes back to normal ~0% idle cpu usage.

I believe MSFT has posted some patch/fix for similar problems with USB drives but I am too scared to try it out.

My System SpecsSystem Spec
28 Apr 2011   #22

windows 7 64 bit

hello guys.. i finally came out of the is wat i did...
i have two hard drives
i opened my cabinet n found out a harddrive was connected to the motherboard and no power was given to it so i removed the connection between the hard drive and the other words i took the unused harddrive out of the cabinet thus totally disconnecting it......

so according to me it could be that a hardware is attacthed to the system but is not getting power supply...... so pplease open ur cabinet n check whether all connections are put in right placed or if there is ny unit like graphic card or harddrive which is not getting the power supply from the psu thought it might be connected to the motherboard.....thus interrupts come when a unit is attacthed to the motherboard but is not getting any power supply
My System SpecsSystem Spec
28 Apr 2011   #23
Microsoft MVP

Vista, Windows7, Mint Mate, Zorin, Windows 8

Thanks for reporting back. That is a pretty unusual situation but good to remember for the next case with a lot of DPCs.
My System SpecsSystem Spec

07 May 2011   #24

Windows 7 Professional x64


I have the same or a related problem on a Toshiba Portege R700-16R.

  • Often after waking up from hibernation, System Interrupts take 25-30% CPU, which is caused by ACPI.sys as seen with Xperf. The problem persists until I reboot. Going back to sleep and waking up again helps sometimes, sometimes it doesn't.
  • In addition, going to sleep mode works only about 90% of the times; sometimes the computer gets stuck in the process with a black screen. I then have to force-turn it off with 4 sec power button.
  • I have experienced, in a few cases, the computer waking up on its own a few minutes after going to sleep mode.
  • I have the impression that USB is involved in the problem, or at least affected by the problem, since the system sometimes has problems recognizing USB devices when the System Interrupts problem occurs. Interestingly, the problem happens with 3 totally unrelated USB "setups":
  • At home, I have a super-cheap USB wireless keyboard/mouse set by Typhoon (which causes problems most frequently, and as a side note, always has to be re-plugged in after waking up from sleep mode or it won't work.)
  • At work, I have a wired USB keyboard and a wired USB mouse (1 USB port each).
  • At my parents' home, I have a good-quality wireless USB keyboard/mouse set by Fujitsu-Siemens.
  • Other USB devices (drives, USB sticks etc.) are attached only occasionally.
  • So while my Typhoon USB wireless desktop is obviously of low quality, I don't think the problem is actually caused by it, because the System Interrupts problem and also the Sleep mode stuck problem occur also when only the wired USB keyboard and mouse or the F-S wireless desktop are attached. To me, it seems like the USB port doesn't handle all events correctly and might have more problems with low-quality devices which are maybe not 100% standard-conforming.
  • Of course, it's possible that USB is perfectly fine and only affected by underlying problems of some other driver.
Any hints on what to do next?
My System SpecsSystem Spec
14 Jun 2011   #25

Windows & Ultimate x64
On Board LAN Card

Quote   Quote: Originally Posted by saik0 View Post

I've had the same problem with ACPI.sys using as much as 60% on one core of my CPU. .....

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.

My MOB has a onboard Realtelk LAN card. After a long period of normal use some how the "Allow this device to wake the computer" option became checked (ok, maybe I did it, but I don't remember it.) One of the CPUs ran persistently at 60% usage and the system slowed to a crawl.

Eventually I tracked the problem down to ACPI.sys. It wasn't till I read saik0's post that I tracked the root cause down to the Realtek NIC. Interestingly the high CPU usage persisted even with the device disabled in Device Manager. It wasn't till I unchecked "Allow this device to wake the computer" and rebooted that the problem was solved.

Thanks saik0. If It hadnt been for your post I would undoubtably still be struggling. It seems you were also right in your assessment of the woth of contacting the MOB manufacturer. I had also loaded the latest NIC drivers.
My System SpecsSystem Spec
12 Sep 2011   #26

Windows 7 Ultimate x32

Hello! My PC struggled with this problem long time. I updated all drivers. Wrong desided that motherboard Asus P5ND2 SE is damaged.

My solution lays deeper - in BIOS. I entered Award BIOS, finded Chipset settings, LDT frequency. It has multipliers x2, x3, x4, x5 whitch change data frequency between south and north bridge. Default was x4. I risked change to x5. If computer became unstable, I could go back and choose another value. SUCSESS.
Returned to Windows 7 and find CPU at 1%.
Aterwards (it is not necessary) changed BIOS value to default, but Windows 7 keeped stability and interrupts at 0%.
That is My case. I think, that it covers driver changing and some other solutions, because it goes deeper - straight into computer stability.
My System SpecsSystem Spec
13 Oct 2011   #27

Windows 7 Home Premium 64bit

Hi guys. I though I am the only one with this problem

The source of my hardware interrupts is also ACPI.sys. One core of the double core processor gets accupied with hardware interrupts even when idle. But it does not seem to be connected with power saving features. It only happens when I play games and the system is under stress. Not likely to be a heating problem (although not sure) as CPU is never above 75 and GPU above 65. The system does not return to normal even after reboot. Only uninstalling/reinstalling/updating some systems utilities helps (like ACPIATK or Intel Management Interface or videocard driver or BIOS update). Then I play for 10 or more minutes and the same problems shows itself again.

I am really lost and do not know what to do

I have a newly bought Asus N43sn notebook, which I do not know and not going to open myself.
My System SpecsSystem Spec
13 Mar 2012   #28

Windows 7 Home Premium
Firewire box was the problem

My excessive hardware interrupts were being caused by a Presonus Firestudio 2626 mic preamp box. I found it by disabling things in Device Manager one by one until I got to the 1394 controller and viola! the interrupts went to near zero. So I reenabled it, interrupts went back up, turned off the Presonus box, and back to zero. Time to RMA (again) or junk it, I guess.

Hope this helps somebody.
My System SpecsSystem Spec
02 Apr 2012   #29

Windows 7 32bits

Hello !

Hardware interrupts are caused by my presonus external sound card too ( a Presonus Firestudio Mobile) ... When I disconnect it , hardware interrupts is normal, otherwise 30 % or more...
Is anybody know how to resolve this point please ?

Thank You !

My System SpecsSystem Spec
15 May 2012   #30

Windows 7 Pro 64 bit

I was having "Interrupts" issue too, when waking my computer up from sleep mode. It was causing my core thread #6 to run almost 100%. I found a solution to the problem. I had turn off my Page Files because I have 12 GB of ram and use a solid state drive. I discovered when I enable hibernate the problem went away, but that uses up 10 GB of drive space and I never use hibernate mode. The trick that worked for me, was to turn Page File back on at no less then 18 Mb. If I set it to 16 Mb, then the problem would came back. Let me know, if this helps anyone. Thx!
My System SpecsSystem Spec

 Hardware Interrupts causing 25% - 30% CPU usage

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