PSU Efficiency Rating

[TheUnk]

How does this work exactly?

If a 1000W PSU is 80% efficiency rating, does that mean it

A. Pulls 1000W but supplies 800W max, because it loses 200W to heat
or
B. Pulls 1200W and supplies 1000W, 200W is lost to heat


I want to think B since they advertise it as a 1000W PSU and not 800W?

 

[TemjinGold]

C. Pulls 1250W and supplies 1000W, 250W is lost to heat.

 

[know of fence]

C. Pulls 1250W and supplies 1000W, 250W is lost to heat.

Similarly to the 1000 W Max, the 80% is some kind of statistical value. I assume 80% min.> at 20%-50%-100% load.

http://www.hardwaresecrets.com/article/Understanding-the-80-Plus-Certification/742/1

 

[jonnyGURU]

A PSU is rated at it's DC output capability. A 1000W power supply should deliver up to 1000W. But if it is 80% efficient, it can pull as much as 1250W from the wall when it is loaded up to 1000W.