Ref: http://www.webupd8.org/2014/04/prevent-your-laptop-from-overheating.html
Because I installed Ubuntu 14.04 in my Lenovo X61.
Although it could switch into the sleep mode after closing the lid. It’s not really using the power saving mode.
So we must edit the GRUB file.
sudo vim /etc/default/grub
Find the “GRUB_CMDLINE_LINUX_DEFAULT”, and add “intel_pstate=enable” at the end, like this.
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash intel_pstate=enable"
Then update the grub config
sudo update-grub
Finally, we must reboot and use powertop to check its status.