Ridiculous PSU question

[Deadpool]

When a PSU says 75% efficiency (let's say a 500W unit), does it mean it'll deliver 500W and dissipate 160W in heat, or the opposite?

 

[StrangleHold]

Its input vs. output. How much its pulling from the wall vs. how much wattage output. But even then it varies by how much load its under.

 

[Deadpool]

Its input vs. output. How much its pulling from the wall vs. how much wattage output. But even then it varies by how much load its under.

So let's say its at full load. It would take 500W from the wall, and would output 375W combining all rails?

 

[beers]

So let's say its at full load. It would take 500W from the wall, and would output 375W combining all rails?

Basically. The rating is in DC wattage though so at the 500w max with 75% efficiency it'd be pulling ~667w from the wall.

PSUs also have an efficiency bell curve that usually peaks around 50% load.