How can CPU be used, but not used?

[Killer42]

Hi all.

Does anyone know what it means when Task Manager "Processes" pane shows 50% or more CPU usage down the bottom, but there's hardly anything in use on the list? Recently I've had a number of cases where the total at the bottom shows maybe 51-52%, but there are only a couple of things ticking over slightly on the list, while "System Idle Process" shows over 90%.

Weird stuff.

[bartonc]

Hi all.

Does anyone know what it means when Task Manager "Processes" pane shows 50% or more CPU usage down the bottom, but there's hardly anything in use on the list? Recently I've had a number of cases where the total at the bottom shows maybe 51-52%, but there are only a couple of things ticking over slightly on the list, while "System Idle Process" shows over 90%.

Weird stuff.

Hey, Killer; would you mind reminding us of your OS and version, please?

[Killer42]

Hey, Killer; would you mind reminding us of your OS and version, please?

Whoops! I should know better by now. :o

Windows XP Professional. Version 2002. Service Pack 1.

It's my work PC so I don't have complete control. My first thought was that there's something running that I'm not allowed to see - boss spying or something, perhaps. But in that case, wouldn't I expect to see some CPU not accounted for? I seem to have CPU being used by absolutely nothing.

[bartonc]

Whoops! I should know better by now. :o

Windows XP Professional. Version 2002. Service Pack 1.

It's my work PC so I don't have complete control. My first thought was that there's something running that I'm not allowed to see - boss spying or something, perhaps. But in that case, wouldn't I expect to see some CPU not accounted for? I seem to have CPU being used by absolutely nothing.

It's weird, alright. The only things I can think of (as you say, you may not have permission, but) there's the check box at the bottom "Show processes from all users" and an option in the Options menu "Show 16 bit tasks". But I'm betting that you have already checked these....

[bartonc]

It's weird, alright. The only things I can think of (as you say, you may not have permission, but) there's the check box at the bottom "Show processes from all users" and an option in the Options menu "Show 16 bit tasks". But I'm betting that you have already checked these....

Never mind all that. Banfa gave a link the other day to M$'s Process Explorer. It's very cool. I haven't checked out Process Monitor yet.

There is no installation needed on the first one. Just run it.

[Killer42]

It's weird, alright. The only things I can think of (as you say, you may not have permission, but) there's the check box at the bottom "Show processes from all users" and an option in the Options menu "Show 16 bit tasks". But I'm betting that you have already checked these....

I certainly do at home. Will have to check at work in the morning. I've got a sneaking suspicion that they are hidden. I know a number of options are.

What I want to know, is how to re-enable them. I can play in the registry, but I'm not willing to unless I know what to do ahead of time - very nervous about touching the good ol' registry.

As for the links, thanks - I'll check them out.

[RevBooter]

before you do anything, would it not be a good idea to get service pack 2 on your machine?

[Motoma]

If you go to the Processes tab and click "Show processes from all users" you should see 'everything' running on your machine. Process Explorer is a good tool to, with many other fun uses.

One other thing to take into consideration, when task manager starts, you will see a processor usage spike. It is the same with most applications. If you have worries about it, take a look at your performance graphs, or order your Processes tab by CPU usage.

[Killer42]

If you go to the Processes tab and click "Show processes from all users" you should see 'everything' running on your machine. Process Explorer is a good tool to, with many other fun uses.

One other thing to take into consideration, when task manager starts, you will see a processor usage spike. It is the same with most applications. If you have worries about it, take a look at your performance graphs, or order your Processes tab by CPU usage.

Yeah, I've always seen a bit of a spike when starting it, just assumed it was the work involved in getting it up and running.

What I don't get is that as far as I can tell, the full 100% is accounted for. If I could only see 49% of the cpu being used, then I'd know it was hiding something. But typically the idle process shows 98% or whatever.

I'm off work today, will have to check my settings Thursday morning.

[Killer42]

before you do anything, would it not be a good idea to get service pack 2 on your machine?

Work PC, one of thousands. Not my call.

[RevBooter]

fair do's :p

[Robbie]

Hi all.

Does anyone know what it means when Task Manager "Processes" pane shows 50% or more CPU usage down the bottom, but there's hardly anything in use on the list? Recently I've had a number of cases where the total at the bottom shows maybe 51-52%, but there are only a couple of things ticking over slightly on the list, while "System Idle Process" shows over 90%.

Weird stuff.

I think I know what you mean. It always happens on my computer, here is a screenshot of it happening now, to make sure this is what you mean.
Screenshot Link

I always assumed it meant for example in that picture, "System Idle Process is using 97% out of the 4% of the CPU currently being used"... meaning that all other processes together are using about 0.012% of the CPU.

[bartonc]

I think I know what you mean. It always happens on my computer, here is a screenshot of it happening now, to make sure this is what you mean.
Screenshot Link

I always assumed it meant for example in that picture, "System Idle Process is using 97% out of the 4% of the CPU currently being used"... meaning that all other processes together are using about 0.012% of the CPU.

Process Explorer will break it down to the .01% per task for you.

I notice that Task manager is scrolled off the screen and can take 4% of the CPU (all these are out of 100%).

[Motoma]

You are reading this wrong; the System Idle Process is not actually a process at all...If you add up the System Idle Process CPU Usage and the CPU Usage at the bottom of the screen, you will get 100% (with rounding errors), ALWAYS. Think of he System Idle Process as the CPU cycles you have left over.

I think I know what you mean. It always happens on my computer, here is a screenshot of it happening now, to make sure this is what you mean.
Screenshot Link

I always assumed it meant for example in that picture, "System Idle Process is using 97% out of the 4% of the CPU currently being used"... meaning that all other processes together are using about 0.012% of the CPU.

[Killer42]

You are reading this wrong; the System Idle Process is not actually a process at all...If you add up the System Idle Process CPU Usage and the CPU Usage at the bottom of the screen, you will get 100% (with rounding errors), ALWAYS. Think of he System Idle Process as the CPU cycles you have left over.

Yes, I was reading about this not too long ago. It's basically the process which does things in the background when the processor is idle, like turning things down to save power.

The way you describe it is pretty much the way I understood it, too. However, I can guarantee that the "ALWAYS" is not correct. Because I have recently seen many examples where they added up to somewhere around 150%. That's what this thread was about.