When I play a movie with SMPlayer (video:mpv) and I check my CPU usage with GNOME system monitor, it shows %4 or %5 CPU usage (1 second update interval), but htop shows %45 CPU usage:

mpv cpu usage

top shows the same load as htop:

top mpv cpu usage

Since My CPU fan RPM goes higher when I'm playing movie with SMPlayer. I suspect top is reporting CPU usage more accurately.

I have Intel i7 920 with 6GB RAM.

Why do I have high CPU usage and why do I see different results on top and in GNOME system monitor?

  • 1
    when in top, press 1 to see percentages of individual cores – Robert Riedl Feb 26 '18 at 7:35
  • 1
    @thomasrutter Through my experience of working on servers, if you have a dual core running 100.00 your system is in major trouble and probably hanging. There is a reason why we use 32+ core systems here as a lot of loaded systems will hit 25.00 in the 1 minute and above. Even this one says that load average of 6.03 on a single core is bad, but on an 8 core is fine. howtogeek.com/194642/… – Terrance Feb 26 '18 at 22:38
  • @Terrance, I am aware that 100 load average is highly overloaded, just pointing out that it is possible. Your previous comment said load average on an 8 core machine could go up to 8. – thomasrutter Feb 26 '18 at 22:41
  • @thomasrutter Yeah, I meant that as you would be fine. – Terrance Feb 26 '18 at 22:42
  • This question is not even close to being a duplicate of that other one, what happened? – thomasrutter Mar 8 '18 at 1:46

Notice that one reading is 8 times higher than the other. You have 8 cores (or execution units). The simplest explanation is that one is calculating it as a percentage of a single core, and the other as a percentage of all eight of them.

According to this, top does indeed show CPU use per process as a percentage of a single CPU core.

  • 6
    This also explains why top can sometimes show processes using more than 100% CPU. On an 8 core CPU, up to 800% can be used – Suppen Feb 26 '18 at 8:11

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.