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A few days ago, my computer started feeling very slow, and looking a CPU usage, I saw that even the simplest processes required a lot of CPU.

As far as I can tell, it's because the core are all down-clocked to 800Mhz, and won't up-clock again when it's needed.

$ cat /proc/cpuinfo | grep MHz
cpu MHz     : 800.000
cpu MHz     : 800.000
cpu MHz     : 800.000
cpu MHz     : 800.000

As a test, I then start up BOINC, to load all my cores to the max, using htop, I see all cores running at > 95%.

My cpu scaling settings:

$ for governor in $(ls /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor); do cat $governor; done

With 'ondemand, I expect the core to clock up, and go to full power, but a watch shows them steady on 800.

To get better performance, I need to manually force it:

sudo bash -c 'for governor in $(ls /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor); do
  echo"performance" > $governor;

Whch immediately changes the frequency to:

$ cat /proc/cpuinfo | grep MHz
cpu MHz     : 2701.000
cpu MHz     : 2701.000
cpu MHz     : 2701.000
cpu MHz     : 2701.000
share|improve this question
Is ignore_nice_load set to 1? Try using stress to simulate cpu load. – psusi Nov 12 '12 at 16:10… – Qasim Jun 14 '13 at 14:36

cat /proc/cpuinfo | grep MHz (or grep MHz /proc/cpuinfo) will only show you the standard clock speeds.

If you want live CPU frequency settings, you need something a little beefier. I know powertop works but for a something convenient all the time, indicator-cpu could be worth it:

sudo apt-get install indicator-cpufreq

You'll need to add indicator-cpufreq to the things to run at start-up, or you'll have to run it manually each login.

share|improve this answer
Actually when I installed indicator-cpufreq from the normal repos it added itself to the start-up items. I didn't have to do it manually. Ubuntu 12.10. – To Do Nov 12 '12 at 13:10
Ok, I looked in powertop since I already had it installed, and I still see essentially 0% in the higher frequencies, even when I load all cores to 100%. – user50849 Nov 12 '12 at 14:12
No, it shows the current clock speeds, as you can see from the different values he posted in the question. – psusi Nov 12 '12 at 16:06

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