Thermal Design Power (TDP) Rating for Processor
Every processor, most notably the Intel and the AMD processors come with a Thermal Design Power or the TDP rating. It is expressed in watts and refers to the amount of power that a cooling system need to dissipate.
The processor with higher Thermal Power Design or TDP rating, “in general”, produces more heat than a processor with lower TDP rating. So obviously, a desktop processor with 55 Watts TDP rating will be producing less heat than a processor with 90 Watts TDP rating.
But can we say with certainty that a processor with 60 Watts TDP rating will produce less heating than a processor with 65 Watts. Well not so sure. We will have to measure the CPU power dissipation rather than the TDP rating.
The TDP rating figure is used by the mechanical engineers to design the heat sink, mechanicals and cooling in a notebook and the desktop design. The thermal simulation is performed, to ensured, that the junction temperature of the CPU does not exceed the rated temperature of the processor. This is done by ensuring that the mechanical cooling arrangement takes out the at least as much heat per second as rated by the processor TDP rating in the worst case temperature scenario.
The TDP rating for a notebook processor typically lies between 15 Watts to 45 Watts. Most common values for the TDP ratings are 35 Watts and 25 Watts. The lower TDP rating will, in general, be preffered, since, the system is less likely to fail because of the mechanical and cooling issues. The desktop processors will in general have TDP rating ranging from 65 Watts to 110 Watts. The desktop processors have in general higher clock frequency and they work at higher voltage. That is the reason they generate more heat and therefore, have higher TDP rating.
More recently the concept of Turbo boost has been successfully used by both Intel and AMD to enhance the real life processor performance. In tubo boost, the frequency of the processor is temporarily increase to cater for increase in the demand of the processing power. The increase in the clock frequency leads to higher power consumption by the processor. As the time passes by, the heatsinks start getting hotter. Before they can reach the threshold value of temperature, the turbo boost is shut down, allowing the processor to cool down. This is one way to increase the real life processor performance while keeping its TDP rating under control.