CPU use is too low while load is high?!

[dcaxax]

Hi all


I have a very weird problem if I can call it that. I have an intel Quad 9300 with an Asus P5Q-Deluxe motherboard (P45 chipset) and 4GB of DDR2 1066 RAM. No overclocking or anything like that. OS is Vista ultimate x64.

I always have very low CPU use, even when my system is doing something CPU heavy e.g. processing graphics filters on pictures in GIMP, encoding audio or video, or doing heavy compression operations (I have many many large archives where I store data).

When I perform one of these tasks I often have to wait and wait but my CPU utilization (an pretty much all cores) never goes above 50%. Only with a CPU benchmark was I able to see the CPU go to 90% and that was only for a few seconds.

So what gives? Do I have a faulty processor? Could my motherboard or RAM be the problem? (I doubt the latter, as I have occasionaly chnage the chips and don't recall any difference).

Any suggestions please please? I'm going crazy here!

 

[GLeeM]

Welcome to the forums!

I'm not sure if it is this way with Vista, but it is with XP.

Windows Task Manager - Processes tab shows 25% for each core. Edit: of a quad core CPU

So if one task is fully using one core it will show 25% usage.

If one task can fully use two cores it will show 50%, if the software can use all four cores then it will show 100% or if you run four single threaded apps then it would also show 100%.

If you already knew this, sorry, I can't help, you will have to wait for more knowledgable help.

 

[dcaxax]

Thanks a lot! I actually did not know that and am really surprised because it shows just how lame x task manager is. Showing 4 cores separately but averaging utilization across them is just crazy!

I will investigate if this applies to vista as well. If anyone knows if this is the case for vista, please chime in...

 

[betasub]

Originally posted by: dcaxax
Thanks a lot! I actually did not know that and am really surprised because it shows just how lame x task manager is. Showing 4 cores separately but averaging utilization across them is just crazy!

I will investigate if this applies to vista as well. If anyone knows if this is the case for vista, please chime in...

Yes, this is typical of the way tasks are handled by Windows (Vista as well as XP). Load balancing allows tasks to be switched rapidly between cores. Thus a task that can only use a single core will use any one core up to 100%, but rapid switching (relative to Task Manager's polling time) between cores results in a load being divided.

You can use the "Set Affinity" option in Task Manager to limit/exlude a task to/from certain cores.