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CPU usage at 100%

8:03 pm on Dec 8, 2006 (gmt 0)

5+ Year Member

My computer is running really slowly and when i open windows task manager it says that CPU usage is at 100% but when i look under processes all say cpu 00 but the numbers flicker every now and again and 99 appears against taskmgr which is open. I just want to know what the problem may be as the computer runs so slow sometimes it is nearly unusable.
9:38 pm on Dec 8, 2006 (gmt 0)

10+ Year Member

You should see which task is grabbing all the cpu.

here are a couple of things to try

1. Try logging on to the machine as another user. See if the problem is tied to one user only.

2. Take a look at the graph in task manager(the performance tab). See if it is totally pegged at 100 or if it's jumping up and down.

3. Take a look at the networking tab in task manager to see if you are using the network or not. Usually this is under .5

4. If something is grabbing all the cpu and not showing in the task manger, it might be a virus. In addition to the other tools you use, see if you can get a copy of rootkit revealer and see if anything shows up there.

5. I've found that on my machine, some websites will cause IE to go crazy. I simply kill the internet explorer process (which closes all IE windoze) and I'm good for a while.

6. Try to think if you added any hardware or software about the time you found the problem.

Hope this helps a little.


7:49 pm on Dec 10, 2006 (gmt 0)

5+ Year Member

Thanks for the help.

1. The same thing happens on all accounts
2. It is always pegged at 100%
3. Not using the network
4. I have run rootkit revealer but do not understand the readout
5. As soon as i load the computer its at 100% usage so it has nothing to do with IE
6. I had a new motherboard fitted but the computer was already running really slow before that it was the reason the new board was fitted.

9:14 pm on Dec 10, 2006 (gmt 0)

WebmasterWorld Senior Member jtara is a WebmasterWorld Top Contributor of All Time 5+ Year Member

Click on the "Processes" tab in Task Manager, and then sort on the CPU column. (Click twice - the first click will sort ascending, the second click will sort descending). This shoudl show you which process is using the CPU time.

Normally, you should see "System Idle Process" as the first item. It is NORMAL for this to be 99% or so if there aren't any processes doing any work.

The system knows about the System Idle Process, and subtracts this from the total on the Performance tab.

BTW, if you have installed some program such as "CPU Idle Pro", which replaces the System Idle Process, the system doesn't know to subtract it from the total, and the Performance tab will show 100%.

5:39 pm on Dec 11, 2006 (gmt 0)

5+ Year Member

All processes say 00 under cpu even the system idle process but the computers cpu usages is still at 100%.
I have not installed any programme like what you described
6:00 pm on Dec 11, 2006 (gmt 0)

WebmasterWorld Senior Member 10+ Year Member

Boot in safe mode. See if that makes a difference. Sweep your computer for junk while in safe mode.
6:23 pm on Dec 11, 2006 (gmt 0)

WebmasterWorld Senior Member kaled is a WebmasterWorld Top Contributor of All Time 10+ Year Member

If I were a betting man, I'd say it's most likely antivirus software at fault and if not that then firewall software (or other security software such as a registry monitor).

Programs of this sort work at a very low level out of necessity and if they go wrong can be very troublesome.

Disconnect from the internet and disable/uninstall all programs of this type one at a time.

Incidentally, you should always state precisely what version of Windows your are using (inc. servicepack) when asking questions of this sort.


6:46 pm on Dec 11, 2006 (gmt 0)

WebmasterWorld Senior Member jtara is a WebmasterWorld Top Contributor of All Time 5+ Year Member

I think you've got some software that's hidden itself from the tasklist, then.

Idle process showing 0% is NOT good.

There's no good reason for any software to hide itself from the tasklist, so probably some kind of virus, spyware, etc.

One more thing to check - In Task Manager, click on Performance tab, then select View, Show Kernel Times from the menu. This will show how much time is being spent in the kernel vs. user programs.

Drivers run in kernel space, so this could be a driver issue.

Try the suggestion above - boot in safe mode, and see if you still have the problem. If not, disable unneeded drivers, and bring them back one by one until you figure out which one it is.

10:12 pm on Dec 11, 2006 (gmt 0)

10+ Year Member

have run rootkit revealer but do not understand the readout

Rootkit revealer should show things that are on the machine but not showing in the API. Usually, you should not have any items listed after you run it. Occassionally there will be an item that shows up and is legit.

If there are items showing, see if you can tell us what they are.

As one of the other posters said, run your antivirus if you can in safe mode.


3:26 am on Dec 14, 2006 (gmt 0)

WebmasterWorld Senior Member billys is a WebmasterWorld Top Contributor of All Time 10+ Year Member

I don't get why everything is zero... look at the CPU time column. System Idle is probably the highest number, but what else is on that list?
12:29 am on Dec 25, 2006 (gmt 0)

5+ Year Member

I had a similar problem with my computer running poorly, tried some software that done the trick (PCTUNER), this software tunes any windows based machine to its highest potential, so if after running this software its still not fast enough (time for a upgrade).

[edited by: bill at 1:55 am (utc) on Dec. 25, 2006]
[edit reason] no URLs, thanks. [/edit]

6:54 pm on Dec 28, 2006 (gmt 0)

10+ Year Member

I spent Christmas eve re-installing Windows on a family members computer.
The reason, he used PCTUNER the day before and the machine would not boot at all. Got as far as the starting Windows step and that was that.

Of course, his machine is now running as good as new and PCTUNER was the reason but not because the program did all the fixing....


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