CPU at 50% usage while idle

Hi,
I have a fresh install of Vista 32 with a P5K motherboard, an Intel 6750 processor, and an NVIDIA GeForce 8600T video card. The computer is acting sluggish. When I look at the CPU usage under the Task Manager, it shows 50+% with nothing running. When I sort the processes by usage, nothing is taking more than 1 or 2%. I have no idea where the other 50% is going. Any ideas? I would greatly appreciate any help.
Thanks,
David
14 answers Last reply
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  1. Had the same problem as well as some other people... None seems to know so far what is causing it. Just make sure you run a few antivirus and antispyware programs and if all is ok, try rebooting. That worked for me.
  2. There are two cpu graphs in task manager, correct? Like darkguset said, might be a virus or spyware, so run some scans and see what comes up. Vista has a lot of background programs running, but it shouldn't go up to 50%.
  3. Thanks for the suggestions. It is a clean install of Vista; so, hopefully no viruses or spyware yet. I have also been rebooting all night...

    I have been playing with this for hours now. I think I have solved it after doing two things - not sure which one actually solved the problem:

    1) Device Manager showed an unknown device with a yellow exclamation point - SM Bus Controller. I downloaded new chipset drivers from intel, and that went away.

    2) I disabled a few things in the BIOS that seemed suspicious (but about which I knew nothing).

    Looks like the problem is now taken care of. I wish I had not done everything at once so that I could be more sure of the exact fix for other forum members. I suspect the 1st but am not entirely sure.

    Thanks again for the responses.
  4. A corrupted driver or open driver from any application or device can suckup resources like a sponge. So can a missing device.

    Rebooting the system can close the driver. Rebooting will not solve a corrupted driver.

    Un-installing and reinstalling devices can fix the problem. A reboot can cause the OS to stop looking for a "missing" device. Re-installing the drivers for the devices can solve the problem.

    Sometimes chasing the problem can take more time that it is worth. As Vista is relatively easy and quick to reinstall, I would evaluate a re-install should the problem continues.
  5. medhead said:
    Thanks for the suggestions. It is a clean install of Vista; so, hopefully no viruses or spyware yet. I have also been rebooting all night...

    I have been playing with this for hours now. I think I have solved it after doing two things - not sure which one actually solved the problem:

    1) Device Manager showed an unknown device with a yellow exclamation point - SM Bus Controller. I downloaded new chipset drivers from intel, and that went away.

    2) I disabled a few things in the BIOS that seemed suspicious (but about which I knew nothing).

    Looks like the problem is now taken care of. I wish I had not done everything at once so that I could be more sure of the exact fix for other forum members. I suspect the 1st but am not entirely sure.

    Thanks again for the responses.


    Yep, #1 sure sounds like the source of the problem.

    Missing devices and unknown devices can be a bytch for the OS as the OS trys to identy the device or find the device which does not exist. ( a bit like being a young mom and looking for your 3 year old that has wandered off while shopping at the mall.... a lot of wasted effort looking in every nook and cranny for a child that is actually sleeping in the teddybear display in the toy department).
  6. I have a new culprit in mind... It is hardware sound acceleration in Windows. When it happens again (not if, because we know by Murphy's law that it WILL happen again, lol) i will try that and see what happens.
    It happened to me last week though, one of the cores fully loaded, but looking at the task list and programs, it showed CPU idle 98%!!
    So it looks like one of the cores is working its a$$ off to do... nothing! LOL!
  7. Did you tryed to click on the button "Show Processes from all users" in the tab "Processes" of "Task Manager"?

    This will show you all processes. The one that is using your CPU will appear! :) Let me know.
  8. check for winlogon.exe
  9. I occasionally have that problem - it is caused by svchost.exe and can be fixed by reconnecting to the internet.
  10. It's only 50% because a single threaded program is freaking out on a dual core system. I commonly see it with the print spooling portion of windows. Do a CTRL-ALT-DELETE and see which process is freaking out.
  11. Well lots of pirated copies of vista floating around have viruses imbedded on them? Not saying you are a pirate but it could be if that was the case.
  12. That is where the problem lies people. You ctrl+alt+delete, check under Processes tab and CPU, but there are 1-2 processes at 1-2% and Idle at 97-98%! No process is utilising the CPU, yet if you click on Performance tab, one core shows up at 100%! LOL! Go figure!
  13. If you haven't already seen this other thread relating to sound HW accel + CPU unhappiness..

    http://www.tomshardware.com/forum/246457-33-usage-staying-more

    What darkguset wrote sounds like a good bet.
  14. Hi all,

    Experienced the same problem on my laptop: Asus G2S 2.2Ghz dual-core, 2gb ram, 8600gt video 32-bit vista

    Today I found a temporary fix that stopped it without requiring a reboot.

    I noticed my pc was running sluggishly and launched task manager. There was the CPU usage at 50-60% with no processes responsible (and yes I clicked 'show processes from all users'). I clicked the 'performance' tab and saw the CPU usage spikes. I hadn't noticed the 'Resource Monitor' button before so I clicked it. And TADA!!! The CPU usage instantly stabilised.

    Launching 'Resource Monitor' requires UAC permission so I assume this reset a flag or something and enabled the 'bad' thread to terminate.

    I don't know, but at least I don't have to reset my computer now every time I experience this issue. I just hope we can find the root cause of the problem sometime soon.

    Let me know if this works for you also.

    Regards,

    Deefa
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