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I have a i3 based system running Windows 7. I have noticed that even during intense activities like copying GBs of data the CPU doesn't exceed 25%. I have no malware.

Some questions based on that observation.

  1. Is that kind of usage normal for such an operation? I haven't done any major 3D rendering and such so I wouldn't know if the CPU might be used closer to 100%. Would it?

  2. Isn't there a way to speed p a long operation by assigning only that to one of the cores and letting other cores do the regular chores?

  3. Is it just a fact that most of us have computers way too powerful for any of our need and CPUs will be inevitably underused?

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For an everyday application that does use all of your CPU, have a look at 7-zip ( 7-zip.org ). Compressing/decompressing big files with it, you should see your CPU at 100%. – schnaader Dec 19 '11 at 19:20
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Why exactly do you want your computer to use more then 20% of your CPU, if it does that, then your performance will suffer. Try running a more resource intensive program, your cpu usage will increase, copying a file is not CPU intensive its I/O intensive – Ramhound Dec 19 '11 at 19:38
"I have noticed that even during intense activities like copying GBs of data the CPU doesn't exceed 25%." How is copying data "intensive"? CPU cache = 100 GB/s, RAM = 20 GB/s, hard drive = 0.1GB/s. Also, the CPU doesn't really do much here. Compiling applications is an example of a CPU-intensive task. – Breakthrough Dec 19 '11 at 19:48
ozone3d.net/benchmarks/fur <== You wanna see 100%? Use this. – WernerCD Dec 20 '11 at 2:23
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2 Answers

up vote 7 down vote

  1. 25% CPU usage is perfectly fine for copying files. The real bottleneck for this is the hard disk (or the hard disk controller), so it is not a CPU intensive task

  2. Windows automatically does load balancing.

    By the way, 25% could mean that you are using 100% of one of your four (virtual) cores.

  3. That depends entirely on what you are going to do with your computer.

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i3 processors have 2 physical cores, but 4 virtual cores due to hyperthreading, so 25% is the typical number you'll see when a single-core application runs at 100% CPU. – schnaader Dec 19 '11 at 19:15
@schnaader: I did not know that the i3 had hyper-threading. Fixed. – Dennis Dec 19 '11 at 19:24
To be honest, I had to look it up myself and also was surprised they have :) - ark.intel.com is a good source for this. – schnaader Dec 19 '11 at 19:34
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up vote 1 down vote

Of course in your example like others have said, what you see if simply because copying files is a hard drive's job, not a CPU job. But the other factor explaining apparently low CPU usage is having multiple cores.

Consider the following example, albeit extreme, of our server at work. It has 8 real cores which are hyperthreaded, totalling 16 virtual cores. Here's the result I get while compressing a big ZIP using one core only:

enter image description here

As you can see, it shows only 7% of total CPU usage, yet the core #3 that is working on it is obviously working at 100%! The reality is that this CPU cannot perform that single task faster, but it has extra parallel power: it could do a bunch of this task at the same time without slowing down an inch!

To view your CPU usage by Core in Task Manager, click on View...CPU History...One Graph Per CPU.

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16 cores, drool, drool. – Moab Dec 19 '11 at 22:11
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