I have a simple question about PSU efficiency (I'm trying to settle a debate with a friend). Let's say I buy a theoretical, totally reliable, able to sustain max load indefinitely power supply rated at 1000W on the box, with an guaranteed 80% efficiency at all loads and temperatures. Which statement would be correct:
1: When PC is drawing all the power it can from the PSU, it will receive 1000W and a Kill-A-Watt would measure 1250W at the wall.
2: When PC is drawing all the power it can from the PSU, it will receive only 800W and a Kill-A-Watt would measure 1000W at the wall.
A rephrase of this question might be "Is the power rating of a PSU the max power it will draw from the wall or the max power is can supply to the PC components?"
Sorry if this has been answered before, I am having a hard time finding this information.
Also, a related question, "Can an 90% efficiency 900W PSU deliver more power to a PC than a 75% efficient 1000W PSU?"