My friend has this strange problem.

While his computer is idling his CPU says 45%, we tried Ctrl + Alt + Delete to see which process is taking all the CPU. But we couldn't see any program that took CPU everything said 00. But still the CPU said 45% and thus his PC was quite slow and laggy. His memory was also pretty high, around 600, but there were no strange processes we could see... He did virus and spyware scans and there were no threats.

Could this be a problem with the hardware or can it be fixed on the computer?

ThankZ.

Give us his computer name (Ex. Dell XPS 600; Compaq Presario 2700T), or if it is a custom build, give us all his specs (have him go to Lavalys.com and get EVEREST if neither of you not sure about his hardware). Be sure to specify his CPU type, speed, and how much RAM he has. Also give us the motherboard's name, if it is a custom build.

Did you try selecting "Show processes from all users"?
If you click the CPU tab a couple times you can sort the processes in order of CPU usage.

Also, you can try downloading Windows Process Explorer. It is a free download from here Process Explorer for Windows v10.21. It is basically the same thing as task manager except its more detailed. There is a CPU usage tracker at the top right of the window where if you hover your mouse over the CPU usage line, it will show you the name of the process that is using CPU time. Also, if you hover your mouse over the processes it will show you what file is requesting those processes.

Hope that helps =D

Thanks for the replies. Wadd, he downloaded the program - and it seems that we found the problem.

DPCs (Deferred Procedure Calls) is taking 45% - 50% of his CPU. What kind of process is this and how can we reduce the CPU is takes?

I also downloaded the program and DPC doesn't take any of my CPU.

it could also be bad drivers, should always use manufacterers drivers over windows ones anyway.
or it could be device conflict which i havent seen since since win98se.

Ok, after searching a bunch of posts and other places, it seems DPC's happen when a piece of hardware tries to interrupt the CPU but doesn't have as high as priority as whatever is already using the CPU. So it starts a deferred interrupt and waits until the CPU is free.

So it seems that this is a hardware related issue that could be a result of defective hardware, device conflicts, or just messed up drivers. I did notice a couple references to network cards causing this type of problem. So what I'd do probably is disconnect as many devices as I could (USB devices, PCI cards, video card if you have on-board). Take as much out that still allows the computer to run. If you're still noticing a problem, then you could either try disabling on-board devices, reinstalling all your drivers, or just do a full system restore to see if that helps. If you still see this issue happening, I could only imagine that one of the on-board devices is defective. If you could find which one it is, you could just disable it and install a PCI version of that device.

I saw this program called Kernrate that tracks what drivers are using the most CPU time and puts the results into an Excel spreadsheet. I have never used this program so I can't give you advice how to use it, but it sounds like it might help you track a faulty driver (if that's the problem). I read that it should be run when you see the DPC start going high. Here is a link to the download Click Here.

Good Luck