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WattFit

Transient spikes and PSU sizing

Averages are for bills. Spikes are for power supplies.

Two different questions

Electricity cost cares about average energy over hours. PSU sizing cares about peaks and continuous 12V capacity.

Using headroom

Estimate system watts, pick a margin (for example 20–30%), ensure PSU continuous rating clears that target. Treat vendor GPU min PSU as a floor, not a personality quiz.

General information, not personalized advice.

FAQ

Is average game power enough to size a PSU?

No. Short spikes can exceed averages; PSU continuous rating and quality matter.

What are vendor min PSU numbers?

Manufacturer system guidance including margin — still verify with your full parts list.

What does WattFit’s headroom tool do?

Compares estimated system watts to PSU rating with a margin % you choose.

Do all 850W units behave the same?

No. Build quality and 12V delivery differ.

Advice?

Educational sizing frame.