What Exactly Does the Wattage Rating on a Power Supply Unit Mean?

[menotu]

Today’s Question & Answer session comes to us courtesy of SuperUser—a subdivision of Stack Exchange, a community-drive grouping of Q&A web sites.

The Question

If I have a system running at ~500W of power draw, will there be any tangible difference in the outlet wattage draw between a 1200W power supply vs, say, a a 800W power supply? Does the wattage only imply the max available wattage to the system?

What is the difference? And what, for that matter, do the 80 Plus designations mean on modern PSUs?

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[µT6]

good information

thanks for sharing