Maximum CPU frequency stuck at low value

The problem was identical to that described on this blog - the BIOS was limiting my CPU frequency, or at least suggested that Linux limits it:

# cat /sys/devices/system/cpu/cpu0/cpufreq/bios_limit 
2000000

To override that you need to type

# echo 1 > /sys/module/processor/parameters/ignore_ppc
# echo -n 2710000 >  /sys/devices/system/cpu/cpu1/cpufreq/scaling_max_freq
# cat /sys/devices/system/cpu/cpu1/cpufreq/scaling_max_freq
2710000

However, in my case the bios_limit seems to be on regardless of whether I run on batteries, or AC. Overriding this limitation works as charm.

You may also need to update grub to force Ubuntu to ignore the bios limiting. This can be achieved by:

Opening the grub file:

sudo vim /etc/default/grub

Replace GRUB_CMDLINE_LINUX_DEFAULT line:

- GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
+ GRUB_CMDLINE_LINUX_DEFAULT="quiet splash intel_pstate=disable processor.ignore_ppc=1"

Update grub:

sudo update-grub

Reboot

Don't know much about this side of things, but i think that cpufrequtils lets you do it by using

sudo apt-get install cpufrequtils
sudo cpufreq-set -r -g performance #-r for related (all) the cores