MERGED QUESTION
Question from Leigh_2 : "PSU Watts lost"
Rogue Leader :
Gold will lose about 10% of its input wattage, and platinum about 8%, but that changes throughout the range of output depending on your load.
I'm not understanding your concern here. The wattage lost is just the difference between the input and what it outputs. That lost wattage is wasted energy basically but for the most part adds up to a dollar or two a year on your energy bill.
I think by "watts lost" you are referring to efficiency. Power is supplied to the computer. Where does it come from? The power plant in your city. Only problem is, as it makes its way to the computer, some of that power goes to waste and is lost as heat. This particularly happens inside the power supply, certain components will heat up (power = heat).
The exact efficiency of a power supply depends on the exact model. The 80+ certification is a general certification that will tell you if one power supply is more efficient than another. An 80+ certified power supply does not necessarily have 80% efficiency. If your PSU is under very minimal or great stress, it will usually be less efficient. So efficiency is not a constant but a variable property of the electronics.
The equation for efficiency is:
Power out is how much power the computer is using. So if your graphics card using 100W, the CPU 50W, and everything else 25W, the power out would be 175W. Power in will be higher, though. As power travels from the power plant, some of it is wasted. So if there is 88% efficiency in this scenario, power input will be ~199W.
There are two adverse effects of having a poor efficiency:
1) The power supply gets hotter. This may cause the internal components to get hotter which can shorten its lifespan. Or if you're the type of person you may like low efficiency so you have a free room heater in the Winter.
2) It costs your electricity bill a bit more money
I say "a bit more money" for a reason. The gains are very small for an average consumer, and if your parents pay the bill, who really cares anyway, am I right? But in general there are a lot more aspects to research into instead of just efficiency. Efficiency is just the bottom of the mountain, I suggest you ask experts for a power supply recommendation, as they have knowledge of the additional properties of power supplies.