What PSU Wattage Do I Need?
Size your power supply from typical component board-power, with a safety headroom baked in.
Sum your components’ typical power draw, add a safety headroom, and get a recommended PSU wattage. TDPs are typical board-power figures, not bare die values.
Result
Choose a 700 W PSU
Estimated load (no headroom)560 W
With 25% headroom700 W
Recommended PSU700 W
Typical load on PSU80%
PSUs are most efficient around 50–70% load. A 700 W unit leaves margin for GPU transient spikes and future upgrades. For a 450 W+ GPU, a good 80 PLUS Gold unit is worth it.
How to size a PSU
Add the typical board-power of each part (CPU + GPU dominate), then add headroom for transient GPU spikes, ageing capacitors, and future upgrades. PSUs are most efficient around 50–70% load, so a unit rated well above your peak draw runs cooler and quieter. For a 450 W+ GPU, choose a quality 80 PLUS Gold unit. Always check the exact wattage and the +12V rail rating on the manufacturer spec sheet.