Thermal Design Power (TDP) is a measurement that tells you how much heat a computer processor, graphics card, or other component will generate during normal use. It's expressed in watts and helps manufacturers design adequate cooling systems.
TDP is not the same as actual power consumption. Instead, it's the maximum sustained heat output the chip is expected to produce. Your CPU might use 45 watts of electricity, but the cooler needs to dissipate 45 watts of heat. This figure assumes the processor is running at full load under typical operating conditions.
Why it matters: A higher TDP means the component runs hotter and requires better cooling. A processor with a 125W TDP needs a more powerful cooler than one rated at 65W. If your case has limited airflow or you're using a compact cooler, a lower TDP component will be easier to cool reliably.
Real-world example: An Intel processor might carry a 65W TDP, meaning your cooler should handle at least that much heat dissipation. An AMD chip in the same performance class might have a 105W TDP, telling you it will run warmer and need more robust cooling hardware.
When buying, compare TDP ratings alongside performance benchmarks. A higher TDP doesn't always mean better performance; it can simply mean less efficient design. Check whether your existing cooler can handle the TDP of a new processor before upgrading. For compact builds or silent operation, choose lower-TDP components whenever possible.