thermal design power
The maximum amount of heat generated by a computer chip or component which the cooling system in a computer is designed to dissipate under any workload.
TDP: the heat your cooler must handle
Thermal Design Power is the maximum continuous heat output, measured in watts, that a processor or component will generate under worst-case load. It defines the cooling capacity a system designer must provision. A CPU rated at 65 W TDP requires a cooler capable of moving at least 65 watts of heat away from the die; a 125 W part demands substantially more robust cooling infrastructure.
TDP is not peak instantaneous power consumption. Modern processors can draw higher current for brief periods during turbo modes or during transients, but TDP represents the sustained thermal load the chip will produce across representative real-world workloads. Manufacturers derive this figure through empirical testing under defined conditions, typically running standardized benchmark suites that stress the chip heavily but do not represent pathological edge cases that might occur only in laboratory settings.
The specification drives practical engineering choices. A laptop with a 15 W TDP processor needs only thin passive heatsinks or compact active cooling. A server CPU rated 250 W TDP requires substantial fan infrastructure, careful thermal paste application, and often redundant airflow paths through the chassis. Exceeding TDP for extended periods causes thermal throttling, where the processor automatically reduces clock speed to cut heat output and prevent damage.
Variants and confusion
TDP varies significantly across processor families and tiers within a family. Intel and AMD publish TDP values for each SKU; mobile processors often have lower ratings than desktop equivalents of the same generation due to power-budget constraints. Graphics processors also carry TDP specifications. The metric can be misleading when comparing across vendors or generations, since testing methodologies differ slightly and some manufacturers rate conservatively while others rate optimistically.
TDP is distinct from actual measured power draw under typical workloads, which is often 50 to 70 percent of TDP for office applications. It is also distinct from maximum theoretical power consumption, which can exceed TDP if the chip operates outside normal parameters. System builders use TDP as a safety margin, not as a description of average runtime behavior, ensuring the cooling solution handles the worst case without failure or unsafe temperature excursions.