TDP stands for Thermal Design Power. It represents the maximum heat output (measured in watts) that a component like a CPU, GPU, or power supply is designed to dissipate under theoretical peak conditions. Manufacturers use TDP to help engineers size cooling systems, but it is not a measurement of actual electricity consumption.
Actual draw, by contrast, is what your device genuinely consumes in real-world use. A graphics card might have a TDP of 320W, yet consume only 180W when playing a moderately demanding game. In everyday browsing or office work, it may draw just 50W.
Why the difference matters: If you only check TDP figures when buying a power supply, you risk either overspending on unnecessary capacity or, worse, choosing one that cannot handle sustained real-world loads. TDP peaks are brief and rare; your system spends most of its time well below that ceiling.
Common issues: Some manufacturers inflate TDP claims to appear more powerful on spec sheets. Mobile devices routinely advertise high TDP values whilst drawing significantly less power. Without actual draw data, you cannot make reliable decisions about power supply sizing, battery life, or energy costs.
What to do: Look for independent reviews or measurements that test actual power draw under realistic workloads. Check manufacturer datasheets for 'typical operating power' or 'nominal draw' figures. For PC components, use power monitors or Kill-A-Watt meters to measure real consumption. When selecting a power supply, size it for actual draw plus a 20-30 per cent safety margin, not TDP.