What are TDP and power limits?

TDP (thermal design power) is the heat a cooler is built to remove. Power limits set the most watts a chip may use, so it stays cool and safe.

1. Power turns into heat
A chip turns almost all the power it uses into heat. Watts (W) measure both: 15 W in, about 15 W of heat out.
2. TDP: the heat a cooler removes
Thermal design power (TDP) is the heat a cooler is built to remove over time. Think of a sink: the tap is the chip, the drain is the cooler.
3. A short burst, then back down
For a short burst, a chip may go above its long-term limit to run faster, like opening the tap wider. Unlike a sink, it turns its own tap down to that limit, which is usually based on the TDP.
4. Current limits protect the wires
Current, counted in amps, is how much electricity flows, like water in the pipe to the tap. Too many amps, even for a moment, can overload the wires and the regulator that feeds the chip, so current limits stop them.
5. Same chip, different laptops
Laptop makers pick these limits, within a range the chip maker allows, and some also limit skin temperature: how warm the outside feels. Big fans make a bigger drain, so the same chip may use more watts and run faster.

Words to know

Watt (W): A unit of power: how much energy is used each second.
TDP: Thermal design power: the heat a cooler is built to remove, in watts.
Power limit: The most watts allowed: long-term for steady work, short-term for bursts.
Current (amps): How much electricity flows through a wire, like water in a pipe.
Voltage regulator: A part that feeds the chip electricity at the low voltage (electrical push) it needs.

Testers set a limit, keep the chip fully busy, and check that its power drops to that limit on time and stays there.

Why can the same chip run faster in one laptop than in another?Think first, then tap to see the answer.

Better cooling lets the laptop maker allow more watts.