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:
top shows the same load as htop:
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?
Best Answer
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,
topdoes indeed show CPU use per process as a percentage of a single CPU core.