Pin Me

Can We Really Know the Normal CPU Usage of a Quad-Core?

written by: theinkandpen (Robert Mullon)•edited by: M.S. Smith•updated: 6/16/2009

If you’ve wondered whether your quad-core processor is under stress (whilst looking at the running processes/Task Manager) read onwards to ease your worries about over-loading the CPU. We will discover the expected usage when dealing with a multi-core processor.

  • slide 1 of 3

    Multi-core processors are the very latest advancement in processor-architecture, at least as far as desktop-oriented PC’s (or Macs) are concerned, and what the everyday user desires. A multi-core is an ideal solution in case you are running multiple CPU-intensive applications; for instance video editing programs, music software or something like Photoshop. In short, multi-core systems are designed to cope with multi-tasking better, with considerable speed increases and reduced overheating problems.

    Since this article will be discussing a quad-core processor specifically (four different ‘brains’ in a single processor) we need to know that most programs are not coded to take full advantage of all four cores (threading). This pretty much makes owning a quad-core system not as useful as one would like; if, for example, we use Photoshop as a benchmark of what power is used, we’ll soon find out that it doesn’t take advantage of full resources but often just one/two of the four cores.

    As a result, we’ll find out that even if one core maxes out at 100% it isn’t really important since you have more power at your disposal. Continue reading to find out typical core percentages for some popular applications.

  • slide 2 of 3

    CPU Usage Percentages

    Since you have four cores at your disposal, maximum CPU usage would be 400%, or 100% of each core presuming that each application is intensive enough to make full use of each core. This isn’t often the case however.

    Using Photoshop as an example again, it may maximize one core at 95%, or thereabouts, while saving or editing a high-definition image. It is unlikely to spread power to more than two cores in any case. This would be similar for other image editing programs.

    Running instances of multiple high-quality videos will likely use less than 25% of each core. However in the case of using editing or capturing programs, such as Windows Media Encoder or an intensive program like Panorama Factory, you will likely take advantage of all four cores and it should result in relatively high percentages. Rendering and encoding applications are mostly the ones that are optimized for a quad and will likely use full resources.

    Most performance-intensive games (such as Quake 4, Elder Scrolls: Oblivion, Rainbow 6) will only use two-cores effectively. Something like the new Elder Scrolls game is likely to use 80% and 20% of two cores, while utilizing very little of the others.

  • slide 3 of 3

    So... What is Normal?

    The answer largely depends on what you are using your computer for. As we have seen, usage varies greatly between applications, and most do not use all four-cores fully. Hence, normal usage in the majority of cases would mean only really employing two-cores.

    Lastly, encoding, rendering and music editing software (i.e Cubase SX4 whilst running plug-ins, VST's etc…) is likely to use up most of a quad’s computing power.