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I have installed Ubuntu GNOME in BIOS mode on my MacBook (BIOS mode so that the proprietary NVIDIA drivers work. I need them for gaming.).

For some reason, a lot of CPU is being used while not really doing anything. It swings between 20-30% on both cores, usually. But when I look at the list of processes and sort by CPU usage, I do not see anything special. No processes intensively doing anything.

How can I fix this?

EDIT: Output of top command.

jop@jop-MacBook:~$ top

top - 17:08:02 up 41 min,  2 users,  load average: 0,51, 0,69, 0,95
Tasks: 202 total,   2 running, 200 sleeping,   0 stopped,   0 zombie
%Cpu(s): 11,9 us,  5,8 sy,  0,0 ni, 80,3 id,  0,5 wa,  0,0 hi,  1,5 si,  0,0 st
KiB Mem:   7908316 total,  2919940 used,  4988376 free,   153248 buffers
KiB Swap:  3906244 total,        0 used,  3906244 free,  1326544 cached

  PID USER      PR  NI  VIRT  RES  SHR S  %CPU %MEM    TIME+  COMMAND           
 3785 root      20   0  195m  82m  26m S  22,9  1,1   2:43.77 Xorg              
 4429 jop       20   0 1543m 150m  60m S   7,3  1,9   1:26.26 compiz            
 4198 jop       20   0  633m  21m  11m S   1,7  0,3   0:04.96 unity-panel-ser   
 7425 jop       20   0  564m  18m  12m S   1,7  0,2   0:00.84 gnome-terminal    
 7019 jop       20   0  806m  89m  46m S   1,0  1,2   0:10.01 chrome            
 7323 jop       20   0  966m  93m  23m S   1,0  1,2   0:06.85 chrome            
 6742 root      20   0     0    0    0 S   0,7  0,0   0:00.43 kworker/0:3       
    3 root      20   0     0    0    0 S   0,3  0,0   0:06.01 ksoftirqd/0       
 7008 root      20   0     0    0    0 S   0,3  0,0   0:00.27 kworker/1:3       
 7302 jop       20   0  972m  96m  28m S   0,3  1,2   0:06.32 chrome            
 7310 jop       20   0  382m  63m  39m S   0,3  0,8   0:00.34 chrome            
 7498 jop       20   0 24840 1600 1120 R   0,3  0,0   0:00.22 top               
    1 root      20   0 27176 2944 1412 S   0,0  0,0   0:01.58 init              
    2 root      20   0     0    0    0 S   0,0  0,0   0:00.00 kthreadd          
    5 root       0 -20     0    0    0 S   0,0  0,0   0:00.00 kworker/0:0H      
    6 root      20   0     0    0    0 S   0,0  0,0   0:00.00 kworker/u4:0      
    7 root      rt   0     0    0    0 S   0,0  0,0   0:02.04 migration/0       

Even when xorg isn't so busy like when I copied, CPU usage is higher then what the processes use.

Strangely, I only have this problem with Ubuntu and Ubuntu GNOME. On Kubuntu, Xubuntu and Lubuntu, I do not have this problem. Has it to do with GNOME's way of doing 3D stuff?

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Can you post the output of top command on a terminal when you feel the usage is high? –  i08in Sep 29 '13 at 17:03
    
It is possible that the tool you use to monitor CPU usage might be using that CPU. E.g. System Monitor uses some CPU to display smooth lines. –  user16538 Sep 30 '13 at 10:28
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1 Answer 1

Seeing unity-panel-service in the top output, it's quite possible that an indicator is being redrawn quite often. That currently causes compiz to refresh the entire screen, which could explain the high CPU usage.

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Do you know how to fix it? And do you know why is the usage not from a particular process? Thanks for trying to help :) –  Jop Vernooij Oct 22 '13 at 15:45
    
Do you see any indicators / tray icons in the panel that are constantly changing? If not this might be a false trail. If you do, try removing them and see if it helps. –  mhr3 Oct 22 '13 at 16:44
    
No. But that's not the problem. The problem is CPU usage that's not connected to any processes. –  Jop Vernooij Oct 25 '13 at 9:49
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