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Locutus65
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Locutus65

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[WIN7] Mysterious CPU usage

Running Win7 Home Premium SP1
Athlon 64 X2 Dual core Processor 6000+ 3.00 GHz
1.5 GB RAM

I noticed this morning my system was responding pretty slow. Rebooted and it was still slow.

I checked Task manager and noticed the total CPU usage at the bottom was way higher than what is showing in all the tasks. The total fluctuates quite a bit.
I also noticed that unlike WinXP there is no System Idle Process.

Here's a screenshot of my task manager. Ideas?



KeysCapt

join:2001-07-11
Carson City, NV

KeysCapt

Tick the "Show processes from all users" box at the bottom and you should see the system idle process line. Click on the CPU tab at the top to sort by that field and see which processes are using it.

(Edit: Looks like you already sorted the CPU column)

Locutus65
Why bother?
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Houston, TX

Locutus65

Premium Member

said by KeysCapt:

Tick the "Show processes from all users" box at the bottom and you should see the system idle process line. Click on the CPU tab at the top to sort by that field and see which processes are using it.

(Edit: Looks like you already sorted the CPU column)

DOH! Forgot to do that. Thanks.
The usage has settled back into a normal range now. Not sure what was going on. I did run a virus scan, malware scan and defrag just the other day and all was clean. Might not hurt to rescan though.


dave
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Not all CPU cycles are used by 'processes' - some CPU use occurs outside process context, notably in interrupt handlers and 'DPCs', which are sort of the nether regions between interrupt handling and process execution.

To see the CPU use for interrupts and DPCs:

Run Performance Monitor and graph the 'processor' counters; they include interrupt and DPC time. Or maybe the Resource Monitor button on the performance tab of Task Manager. Or sysinternals Process Explorer.

In earlier times, the instant diagnosis for runaway interrupt use was something connected to the parallel port. Now I'd guess it's probably something connected to USB.
19579823 (banned)
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quote:
I also noticed that unlike WinXP there is no System Idle Process.
What exactly does SYSTEM IDLE PROCESS tell you?

I have always wondered.... Im on 98se and I just looked @ mine now and it says 75.20 (It keeps changing) .. Does that mean how much CPU power is in reserve?
dave
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not in ohio

dave

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Approximately speaking, the system idle process is a process like any other. It does nothing. It is selected to run when nothing else is runnable (i.e., it has the absolute lowest execution priority in the system).

100% of CPU cycles are used all the time. When we say the CPU is 15% busy, it really means 85% of the CPU got used by the idle process, and the other 15% was used running allegedly useful things.

There is no 'in reserve' in CPUs. CPU cycles just happen, the same way the seconds of your life just happen. (Though admittedly the rate at which CPU cycles pass by is variable, in modern CPUs).

But, yeah, you can still look at it as 'available for use'.

andyross
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Re: [WIN7] Mysterious CPU usage

Today is Windows Update day. Maybe it was doing a scan to see what is available? It could also have been something like Indexing or defragmenting running in the background?
OZO
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Re:  

said by 19579823:

What exactly does SYSTEM IDLE PROCESS tell you?

It tells, what CPU time is not used by any other processes on the system.
19579823 (banned)
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Merci Beaucoup guys,it explains that process more!

deke40
deke40
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Texas

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Re: [WIN7] Mysterious CPU usage

Click for full size
Here is a visual of what Dave mentioned.
dave
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dave

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Click for full size
This, too, for interrupt/DPC usage.

bbrcat
Remembering Lisa...
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Obvious I know, but running any type of DC aplet(such as your Seti@Home) taxes CPU usage, depending on how much it is allocated to use...
WhyMe420
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Re:  

said by 19579823:

quote:
I also noticed that unlike WinXP there is no System Idle Process.
What exactly does SYSTEM IDLE PROCESS tell you?

I have always wondered.... Im on 98se and I just looked @ mine now and it says 75.20 (It keeps changing) .. Does that mean how much CPU power is in reserve?

On top of what everyone else said, System Idle Process also executes power-saving functionality in the CPU when it's not being used.

hortnut
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join:2005-09-25
PDX Metro

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Re: [WIN7] Mysterious CPU usage

I run Process Explorer v15.13 I feel it gives me a lot more info. and control than just Task Manager.

By Mark Russinovich

"Ever wondered which program has a particular file or directory open? Now you can find out. Process Explorer shows you information about which handles and DLLs processes have opened or loaded......"
»technet.microsoft.com/en ··· bb896653
19579823 (banned)
An Awesome Dude
join:2003-08-04

19579823 (banned)

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quote:
I run Process Explorer v15.13 I feel it gives me a lot more info. and control than just Task Manager.
It sure does!!!!!

Arent they all the same??? -- No need to get a newer version,THEY ALL ARE EXCELLENT! (I have v9.25 and its incredible)