High CPU usage despite Idle at 99%?

Discussion in 'General Software' started by kumquat, Dec 13, 2007.

  1. kumquat

    kumquat [H]ardness Supreme

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    [​IMG]

    [​IMG]

    What the hell? How does that happen?
     
  2. bbz_Ghost

    bbz_Ghost 2[H]4U

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    Are you on a dual core machine? Or something with more than one core or CPU? If so, bring up Task Manager, click the Performance tab, click View on the menu bar, select CPU History and make sure "One Graph Per CPU" is selected. That way you get to see all your cores. This is the most common reason Task Manager will show conflicting CPU usage reports just like yours.

    If you're not on a dual core machine/dual CPU, then something is seriously wrong. :( Try running System File Checker from the Run box: Start - Run - sfc /scannow (press Enter). If any files are corrupt in your machine, it'll need the XP CD to restore them to original digitally signed states.

    Hope this helps...
     
  3. nessus

    nessus 2[H]4U

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    Click the show processes from all users checkbox...

    Processes running under the authority of your user aren't using any CPU. Your process list is limited to just that without the checkbox checked.

    The other tabs aren't limited to just your user activity, they show real totals. Nothing strange going on at all.
     
  4. kumquat

    kumquat [H]ardness Supreme

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  5. OldMX

    OldMX 2[H]4U

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  6. kumquat

    kumquat [H]ardness Supreme

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    Nothing shows up in the HijackThis log that doesn't show up in Task Manager.
     
  7. bbz_Ghost

    bbz_Ghost 2[H]4U

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    So, I'll ask again: are you using a dual core processor, or a dual CPU machine? If you are, and you have Task Manager set to show only one graph for both CPUs/cores, it'll cause the "issue" you're having.
     
  8. kumquat

    kumquat [H]ardness Supreme

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    Sorry, it's a P4 with HT. Doesn't matter whether the display is one for both CPUs or one for each CPU. "System Idle Process" stays at 99 and CPU Usage stays at 50+.

    This isn't my computer, but I can't for the life of me think of any way this can happen. It's sort of a problem I'm trying to diagnose remotely.
     
  9. bbz_Ghost

    bbz_Ghost 2[H]4U

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    Ok, just wanted to make that clarification. With HT, you should leave the "One Graph Per CPU" setting the two "processors" will show properly in Task Manager. If the HT portion of the CPU is maxed out for whatever reason (a logical processor, not a physical one), and the actual physical processor isn't (weird how that works but it's possible) it'll throw off the percentage reading for total CPU usage.

    There were a few instances in the past (several years now) where I had a client's machine that would do the same thing that the one you're trying to diagnose and repair is doing. Turned out to be an antivirus app he was running, some $5 cheap bargain software he grabbed at checkout in a computer store (impulse purchase on the way out the door, basically). It caused the "logical" processor on his P4 3.0 w/HT to peg out, but the actual processor rarely ever went over 40% or so. Couldn't understand it then, still don't really, but we got rid of that crappy software and got him a proper NOD32 installation anyway.

    Good luck, regardless...