I tested CPU frequencies with either the Intel tool i7z
and turbostat
from the linux-tools
package (sudo modprobe msr
, sudo turbostat
) and what I find as maximum frequencies for two different processors is lower as what Intel states as maximum turbo frequency.
I tested with MrBayes MPI on 4 cores with governors ondemand
and performance
and the 'turbo' option using indicator-cpufreq
.
i5-3210M - Intel specifications max. freq.: 2,5GHz - 3,1GHz Turbo
max. measured: 2,89GHz
i5-3470 - Intel specifications: 3,2GHz - 3,6GHz Turbo
max. measured:3,39GHz
I also tried for i in {1..4}; do burnK7 & done
in tty1 and turbostat in tty2 and got the same results.
Why are the max. Turbo CPU frequency I can measure running Ubuntu lower than the ones Intel states? Where are the "missing" 0,21GHz?
burnK7
. It's old but should stress out a single core and cause it to enter turbo.sudo service lightdm stop
to stop graphical processes that would be running in the CPU and run thiswhile :; do :; done
while in tty2 you execute thesudo turbostat
or i7z monitors.