99% CPU on Win8.1, Can't find offending process

For the last several weeks my laptop is running at 99% CPU, and have been unable to find the offending process.

Task manager shows 99%, with no one process using all the CPU, it cycles between several processes with no consistent culprit, but they only add up to about 60% anyway. If I kill tasks that are the bigger users, other tasks just rise up and start using more. Resource monitor also shows high CPU, on each processor, but nothing in the process list.

Looking at Process Explorer (running as administrator), it only reports about 2% usage. I know it's using more though as my battery life is rubbish, and the fan is constantly on.

Searching high and low, most posts point to driver interrupts, but I don't see the same symptoms, so am now stuck. I have run a full virus scan, with no alerts.

If anyone can suggest where else I should look, I would greatly appreciate the pointers.

-----------Update 1--------------

I have booted into Safe Mode (minimal), and still see full CPU in Task Manager

-----------Update 2--------------

I couldn't get to the bottom of it, so formatted and re-installed windows from scratch. That fixed it :)

Xperf trace run as admin

https://www.dropbox.com/s/ap684b7ekuv8zq2/HighCPUUsage.zip?dl=0

Task manager output

Process Explorer output Proc Explorer

Resource Monitor output

BlinkyBill

Posted 2014-10-26T07:03:25.110

Reputation: 159

provide a xperf trace: http://pastebin.com/pgE11HRD

– magicandre1981 – 2014-10-26T07:15:29.257

magicandre1981: xperf trace run as administrator can be downloaded from https://www.dropbox.com/s/ap684b7ekuv8zq2/HighCPUUsage.zip?dl=0

– BlinkyBill – 2014-10-26T07:24:46.940

@BlinkyBill I've seen this issue before with a clients' laptop, turned out they were infected with a trojan botnet when from a rogue driver installation package they downloaded. *The only solution to this is a complete wipe/reinstallation of Windows- ensure you have your program settings & important files backed-up first!* – AStopher – 2014-10-26T07:47:55.770

1@cybermonkey, no offence, but will wait for that to be clarified by a user with higher rep, before going that drasatic step. – BlinkyBill – 2014-10-26T07:58:33.777

@magicandre1981, just to be clear, you're saying I should trust the trace and disregard task manager? – BlinkyBill – 2014-10-26T08:00:01.610

@magicandre1981 I specifically asked for you to *stop insulting others. This has been passed onto the Stack Exchange team.* – AStopher – 2014-10-26T08:12:27.750

1@BlinkyBill Is there anything you remember installing/uninstalling at the time the high CPU usage started happening? How's the internet speed on the laptop, is it the expected speed or slower than expected? – AStopher – 2014-10-26T08:13:39.757

@cybermonkey, the only factor I could put it down to was a BIOS update and some driver updates. They were taken care of via Lenovo's driver update tool, so no third party driver packs. So stumped. – BlinkyBill – 2014-10-26T08:19:11.033

@BlinkyBill What model laptop is this? I have a Lenovo laptop myself and never experienced high CPU usage after any updates via the Lenovo Update tool, so I doubt that that'll be the cause. – AStopher – 2014-10-26T08:22:41.513

@cybermonkey, Lenovo T440S – BlinkyBill – 2014-10-26T08:23:49.520

@BlinkyBill If you boot your laptop up in safe-mode, what is the CPU usage like? – AStopher – 2014-10-26T08:24:43.350

Let us continue this discussion in chat.

– AStopher – 2014-10-26T08:24:47.990

4I'm voting to close this question as off-topic because the problem went away and can have no clear answer. – psusi – 2017-04-23T01:52:41.003

Answers

Ensure you are running Task Manager with admin rights, as it will not show processes run with administrator rights, if the user does not have administrator rights and therefore omit to show the processes which may be causing the high CPU usage.

To do this, open a CMD window with admin rights and it will show "Administrator:" in the title bar if it is run with admin rights. Then run the command taskmgr.exe

MikeC

Posted 2014-10-26T07:03:25.110

Reputation: 132

You have no CPU usage in the trace. The CPU is idle for 99%:

enter image description here

Resource Monitor shows 104% CPU usage so this is a bug and you can ignore this.

magicandre1981

Posted 2014-10-26T07:03:25.110

Reputation: 86 560

1Not an answer.. this is better suited as a comment. – AStopher – 2014-10-26T07:43:57.377

1@magicandre1981, This is the problem. Task manager and Resource monitor show 99%, while Procmon and this trace show no CPU usage. – BlinkyBill – 2014-10-26T07:55:43.040

@magicandre1981, ok I think I'm with you now. You're saying there's a bug reporting bad CPU readings in task manager/Resource Monitor, as evidenced by the 104%. – BlinkyBill – 2014-10-26T08:02:41.703

@magicandre1981, looked into CPU usage > 100%, and it looks like it has to do with CPU performance scaling, so an >100 reading is valid. More detail at http://superuser.com/questions/256921/what-does-the-maximum-frequency-number-mean-in-the-windows-resource-monitor.

– BlinkyBill – 2014-10-26T08:22:09.980

On my PC, this problem seemed to be caused by one of the Balanced power saver mode. Simply switching to High Performance or Power Saver fixed this problem for me.

Now, Task Manager shows the correct amount of CPU usage.

nomad

Posted 2014-10-26T07:03:25.110

Reputation: 1

Resource Monitor says "104% Maximum Frequency". The processor is not throttling. Quite the opposite, in fact: the processor is operating at Turbo speeds. This therefore can't possibly explain the issue. – bwDraco – 2015-03-18T06:41:46.827

-1

I had the same problem. Turns out a program (Steam, if you must know) was being showed incorectly. It was using up loads of CPU but the task manager reckoned it was only using 23%. Check if any program is constantly updating or performing background tasks?

Luke

Posted 2014-10-26T07:03:25.110

Reputation: 1