Ubuntu get actual current CPU clock speed
Solution 1:
To know all your CPU Specs use the command:
lscpu
To get the specific frequency of your CPU use the command with a grep like so:
lscpu | grep MHz
It will give you output like:
CPU MHz: 2723.789
To see realtime CPU speeds fluctuation use :
watch -n1 "lscpu | grep MHz | awk '{print $1}'";
Solution 2:
Your system is probably using intel_pstate driver.
Setting this driver's governor is very easy. To set all CPUs to maximum frequency, just use the following command:
echo 100 | sudo tee /sys/devices/system/cpu/intel_pstate/min_perf_pct
To do the opposite, and force low power on the CPUs, issue:
echo 20 | sudo tee /sys/devices/system/cpu/intel_pstate/max_perf_pct
Where 20 is the percentage of maximum performance you want to allow. Setting this to 10% will probably result in extremely sluggish GUI, but you can try and see.
Sources: kernel.org