High CPU Usage but No High Program Usage other than Idle



I have seen a few posts about this problem, but no solution or
explanation. Any thoughts are appreciated. In short, 80% CPU usage,
but no processes doing it (only Idle showing 80-99% use).

Please read this carefully, it's a strange problem, not just a
misunderstanding. Based on my web search, it has occurred wtih NT and
XP computers, and no one has offered an explanation or solution.

Windows XP.
Task Manager--Performance Tab--shows CPU Usage hovering around 80%.
Same thing with perfmon.

Here are more details if they help: Commit charge is 421M / 4,285M

Running 62 Proceses (9 of them scvhost.exe)

Task Manager--Processes--most at 00, with one or two flickering up to
10 or 20.

System Idle is at 80 to 99% the whole time.

Page File Usage is almost nothing. PF Usage is 416 MB. Total Memory
is 3 Gigs, with 2.5 Gigs available and a system cache of 1.4 Gigs.

Commit Charge is a total around 426, 340, with a peak of 471,668 and a
limit of 4,388,464.

Kernel Memory is a total of around 97,000 with around 74,000 paged and
around 22,800 Nonpaged.

Same symptoms when running in Safe Mode.

I *think* that the computer takes more time than it should to do basic
tasks, but is not unreasonably slow.

I have Norton Internet Security Running and have run all sorts of
(legitimate) spyware checks with nothing found. I have done a full
scan for viruses.

What gives? Under these circumstances the Performance *should* be
below 20% or close to 0%. Is there a real problem here?

As they say on Car Talk--it's a puzzler.


System idle of 80 to 99% is normal, this means the CPU is not being used.
However anything else would indicate some process is causing the problem. If
you want to dig deeper into the problem (if there is one) see below.

Try Process Explorer:

Once you have Process Explorer installed and running:
In the taskbar select View and check 'Show Process Tree' and 'Show Lower
Pane' options.
(This will provide the detailed info you need)
Next click on the CPU column to sort processes by %CPU usage.
Then click on the process that's using most or all the CPU %,
once it's highlighted, right click and from the options listed select:
This should display what out there on the web about that process.

Note: some entries like Explorer and svchost may need to be expanded to show
the detail,
(sub processes), in this case click on the + located to the left on the

Still another tool is What's Running



I have Norton Internet Security Running

Try disabling that for a while, if it will let you, and see if speed
improves. Many claim Norton and McAfee are big resource hogs and
really slow things down.


Thank you. The investigation is on.

I installed Process Explorer (handy!)

Hardware Interrupts fluctuates between 60 and 70 % of CPU usage.

So I searched for information on that.

I found the following two discussions, which I must admit are far
above my head. So my newly refined question (plea) is if there is a
best method of hunting down the problem here, without risking some
fundamental system crash (I'd rather live with the problem then have
to wipe my computer). I'm comfortable doing things that disabling
hardware, and basic registry edits, but I must admit that I do so

1) http://forums.viaarena.com/messageview.aspx?catid=16&threadid=75671

or: http://tinyurl.com/22vg7z

The entry that I found promising is Mon Jan 08, 2007 22:58 by Boast:

well, I just enabled the VIA usb controller to see the irq and what
not, and its fixed. CPU usage is low. weird.


or http://tinyurl.com/yslpfz

The entry that I found promising (although I'm not sure which
suggestion was the good one) is

View profile
More options Apr 16 2005, 10:51 pm
Newsgroups: microsoft.public.windowsxp.perform_maintain
From: Navile <[email protected]>
Date: Sat, 16 Apr 2005 19:51:08 -0700
Local: Sat, Apr 16 2005 10:51 pm
Subject: Re: High CPU usage due to Hardware Interrupts
Reply to author | Forward | Print | Individual message | Show original
| Report this message | Find messages by this author
Your suggestion worked, Thanks very much. Although it was not one of
the USB
controllers, it was "OHCI Compliant IEEE 1394 Host Controller" There
another IEEE 1394 Host Controller, and that is OK, but this one was
the problem. I Disabled it. When I Uninstalled it, it came back again,
with Disabling it is OK.

Thanks to all others who tried to help.


Kerry Brown

That's a classic sign of a bad driver or some hardware actually gone bad.
Physically remove or disable in the BIOS everything that's not needed to
boot the computer. Add things back in one at a time until the problem starts


Say it isn't so. I can't believe that I have to resort to a hit or
miss approach (which I just can't do--too much time and too much risk
that I'll disable something that I shouldn't). Perhaps I'm naive, but
I have hopes for actual diagnostic work.

Isn't there anything that can tell me what hardware drivers or
hardware are sending these interrupts? Process Explorer took me one
step further than Task Manager. Won't something else take me one step
further and identify the source(s) of the interrupts?

I submit my inquiry to the ether of the internet. Thanks to everyone
who has responded so far, especially JS.


Your welcome, sorry you came to a dead end but there is another tool (don't
known how much it will help) but have a go at it.http://www.microsoft.com/technet/sysinternals/SystemInformation/proce...

Good Luck

- Show quoted text -

I wrote a few self help sheets on my blog see if these help especially
the first part of section 2 mentions Hard Drive Being Constantly Paged
But No High CPU

Windows XP Is Running Slower Than Normal Fix Sheet Part 1


Windows XP Is Running Slower Than Normal Fix Sheet Part 2


Free Guide To Fixing Your Own Windows Problems


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