I recently purchased a laptop with a sandy bridge CPU that is supposed to have turbo boost. Is turbo boost supported in 11.04? How can I tell if it's working?
7 Answers
11.04 runs the 2.6.38 kernel which is supposed to work well with Sandy Bridge CPUs.
You can open a terminal and run grep MHz /proc/cpuinfo. Then open a second terminal tab and run a loop like while :; do :; done. In the first terminal, run grep MHz /proc/cpuinfo again. You should see one of the cores has a higher frequency now:
$ grep MHz /proc/cpuinfo
cpu MHz : 1600.000
cpu MHz : 1600.000
cpu MHz : 1600.000
cpu MHz : 1600.000
cpu MHz : 1600.000
cpu MHz : 3701.000
cpu MHz : 1600.000
cpu MHz : 1600.000
You can also try powertop and turbostat from the linux-tools-common package (run sudo modprobe msr before sudo turbostat). The Git version of i7z is supposed to work for Sandy Bridge (and it works for me with a desktop i7).
Use sudo turbostat for this. The output of cat /proc/cpuinfo does not always show the real current CPU frequency but instead the maximum non-turbo frequency even when Turbo Boost is enabled and active.
As stated in elmicha's answer, you'll need to load the msr module with sudo modprobe msr and then run turbostat with sudo turbostat.
Accepted top voted answer doesn't always work
As the second top voted answer pointed out, the top voted and accepted answer sometimes shows the maximum regular frequency.
Alternate CLI methods
Below you can see frequencies for CPU Number 0. To see all CPU's replace 0 with *. The frequency is expressed in MHz with three decimal places. So 1000000 = 1000 MHz = 1 GHz. This Intel Skylake processor is rated to 2.6 GHz or 3.5 GHz with Turbo Boost enabled.
Minimum frequency 800 MHz
$ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq
800000
