# ntoskrnl.exe threads hosted by system Idle process load 100% CPU



## serrnovik (Sep 23, 2012)

Hi

I’m experiencing very annoying issue. CPU loaded with System Idle Process always. Because of that there is serious lag in iterfase. Problem appeared almost sumultaniusly on there different PCs. Using “Process Explorer” and going to System Idle Process - Threads I’ve found processes with names:
ntoskrnl.exe!KiDespatch Interrupt+0x650 (on one PC)
or
ntoskrnl.exe!KiCpuId+0x6a0 (on two others)

I have three diffenent machines - one old acer laptop, one modern desktop and wmware virtual machine running on macbook. All have same OS - win 7 ultimate sp1. All of them are in the same network.

I’ve tried to localise issue by removing services and applications from startup - nothing, I’ve scanned machines with microsoft security essentials, Dr Web CureIT and Kaskpersky virus removal tool. Still nothing.

CPU get loaded as soon as system starts. Number of ntoskrnl.exe instances equals to number of CPU kernels. 1, 2 and 8 in my case on different PCs .

I’ve been googling the whole Sunday - nothing helped. Some suggest that it is hardware related... apparently it is not as it happend to three complitely different computers.

Can’ anyone suggest what else can I try?


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## satrow (Feb 4, 2012)

Welcome to TSF.

From what I see here, the System does not have enough RAM and a lot of TCP/IP traffic has just begun. As the 'problem' occurs on 3 machines, have you tried rebooting the router/switch/hub (common factor)?


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## serrnovik (Sep 23, 2012)

I've been flowing for a while topics on this forum and they was quite helpful... hope i'll find answers to my problems with my first post.

I've tried to eliminate network factor. I've tried to boot with and without network adapter turned on - same result. 
desktop has 12gb. I don't think it is about RAM. Also even on old laptop with 2gb RAM CPU get loaded right after start up and there is about 1.3 - 1.5 gb RAM used. And it all began without and serious configuration change.

Also I've tried to reload router.... nothing.


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## LMiller7 (Jun 21, 2010)

The System Idle Process isn't the problem and isn't a real process at all. In practical terms it is simply a measurement of the CPU time that is not in use. The higher the number the better.


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## serrnovik (Sep 23, 2012)

LMiller7 said:


> The System Idle Process isn't the problem and isn't a real process at all. In practical terms it is simply a measurement of the CPU time that is not in use. The higher the number the better.


The question is where is the lag is coming from...

Ok, thank you for information. I'll keep monitoring... maybe it is something different that is wrong.


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## satrow (Feb 4, 2012)

There's no sign of any CPU lag; as the memory usage looks to be ~80%, you'll need to look into what's being used in the way of virtual memory - writing to disk - if you only have 1 disk with virtual memory allocated to it and it's the Windows System drive, it may be that disk I/O is high and using kernel time.

Alternatively, you may have a 'bad' driver somewhere that is also using kernel time.

Any kernel time usage is at a much higher priority than user processes, when it happens frequently or over more than a second or two, you feel lag.

To get a view of kernel time, open Task Manager to the Performance tab > View > *Show kernel times*. You'll now see a new red line in the graph. As a rough guideline, sub 5% red means you'll not feel lag, ~ 8-10% and it will probably feel a little laggy, over 20% and the lag feels bad.

Seeing high kernel times while a program is opening, or closing down, is normal and to be expected. If you have a machine with an Intel graphics chip and you play a video, you're likely to see high kernel times - it's normal - with a good graphics card, the GPU will do (almost) all the work, leaving CPU% very low - *if* the drivers are good!


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## serrnovik (Sep 23, 2012)

Thank you for your answer and explanation about kernel time - I didn't know about that. I'll continue monitoring.


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