up vote 1 down vote favorite
1
share [g+] share [fb]

Possible Duplicate:
Task Manager shows 100% CPU utilization, but nothing in process list does.

My friend has a machine in his teashop that I am attempting to troubleshoot, so far with minimal success. It is a WinXP, 500MB, 2.12GHz. Nothing spectacular by today's standards, but a reasonable piece of equipment.

In the last couple of months, it has started a behavior that I have so far been unable to repair. When the machine sits idle for a while, it suddenly jumps to 100% CPU usage for no apparent reason. It has WinAmp running almost constantly, playing background music in the teashop, and usually a browser open, which the owner plods around on the net when not busy with the shop. This all works well and when WinAmp is running, usage is around 3-5%, as one might expect.

But when the owner leaves the computer idle for some time, the usage suddenly jumps to 100%, to the point where WinAmp can't even keep up - the played sound stutters so badly it's unrecognizable as music. This continues for around ten seconds, then stops, then resumes fifteen to twenty seconds later, stops again, and so on. It only quits when someone moves the mouse or presses a key. This happens regardless of whether a browser is open or not, and I've tried all three of the biggies.

The process names window shows nothing using that much power, although the CPU utilization line is at 100%. And it's almost impossible to do any research into the problem, because as soon as I move the mouse, it stops. I have an anti-virus (NOD32), have checked for spyware, unloaded everything suspicious from the start-up configs and installed a load balancing tool called ProcTamer. Nothing has helped.

Can anyone suggest something to try?

link|improve this question
As mentioned, try running Process Explorer as administrator, if it is the System process then it are most likely driver problems. Try the second part of an earlier answer (about Windows Performance Analysis Toolkit) in that case to get an idea which driver is causing the problem... – Tom Wijsman Mar 31 '11 at 14:08
feedback

closed as exact duplicate by kez, ChrisF, Tom Wijsman, studiohack♦ Mar 31 '11 at 14:08

This question covers exactly the same ground as earlier questions on this topic; its answers may be merged with another identical question. See the FAQ for guidance on how to improve it.

3 Answers

up vote 3 down vote

One way to diagnose this might be to open the task manager pre-emptively.

Switch to the "Processes" tab and enable the "Show processes from all users" option. Then sort the grid by CPU - a single click on the heading of the CPU column should do this (click again if System Idle Process isn't at the top).

Then when the problem starts you should be able to look at this view and see what's now at the top of the grid. Make a note of the process name then search using Google or ask another question for more information.

link|improve this answer
Chris -> Okay, thanks, I'll give that a try. I'd try it right now, but the shop is where I go some evenings. Next visit, I'll see what this shows and post back – pdanes Mar 31 '11 at 13:48
feedback
up vote 2 down vote

I would suggest delving deeper into the process list using Microsoft's ProcessExplorer. It will show you all the resources all the processes are using, and even make you some nice graphs to look at. It should pinpoint the process that's doing the dirty on you.

link|improve this answer
Thank you, I'll try that as well. – pdanes Mar 31 '11 at 13:46
feedback
up vote 1 down vote

Does the system have a screen saver when it has been idle? Some of the 3D screen savers will use 100% CPU and impact other processes.

link|improve this answer
No, there are no screen savers running. – pdanes Mar 31 '11 at 13:48
AFAIK, screensavers are started at "Idle" priority class, so they cannot impact other processes. (They can use up 100% CPU, but only if no other program needs it.) – grawity Apr 1 '11 at 14:23
feedback

Not the answer you're looking for? Browse other questions tagged or ask your own question.