Go to Control Panel > Power Options
Create a new Power Plan. Name it acc to your choice
Then select this new plan > Change Plan settings > change advanced plan settings > Processor power management
Change MAXIMUM Processor state (not minimum) according to your need (explained below)
Changing to 99% disables Turbo boost
Changing to lower percentage like 90 or 80 lowers CPU frequency as well as voltage.
You can choose to keep 100% when plugged in and 90% on battery Then vary it according to your needs.
This method undervolts and underclocks your processor. It uses Intel Enhanced SpeedStep technology to do so
Devices Samsung GT-N7100, Sony Ericsson ST15i