Actually all the people are answering from theory and books. I personally tried setting the maximum processor state at 30% and gain only 1 degree Celsius in overheat. I undervolted the processor to the minimum of getting a BSOD in 5 minutes of stress, and gained another 1 degree Celsius. I stress the fact that the laptop is new, a Lenovo E540, with cleaned exhaust channels, clean fan, new Thermal paste (best and most expensive on the market - about 25$ a very tiny bottle). All this effort for only 2 degrees Celsius. This is because it's kind of a cheap laptop for Lenovo, not in the T or W series. The heatsink is very poor, and nothing on Earth can cope with that. The processor likes to stay at around 50-52C when idle, and 70-75C at load. These figures are with the above tweakings and without. Please stop answering different things if you don't know what are you talking about, and especially if you didn't try it yourself.

Actually, all the people are answering from theory and books. I personally tried setting the maximum processor state at 30% and gain only 1 degree Celsius in overheat. I undervolted the processor to the minimum of getting a BSOD in 5 minutes of stress, and gained another 1 degree Celsius. 

I stress the fact that the laptop, a Lenovo E540, is new, with cleaned exhaust channels, clean fan, new Thermal paste (best and most expensive on the market - about 25$ in a very tiny bottle). All this effort for only 2 degrees Celsius. This is because it's kind of a cheap laptop for Lenovo, not in the T or W series. The heatsink is very poor, and nothing on Earth can cope with that. The processor likes to stay at around 50-52C when idle, and 70-75C at load. These figures are with the above tweaks and without.