Power Supply 400W 550W 650W... ?

[ALIVe_]

Something I really haven't got the hang of is, what's the difference betwen a power supply that is 400W 550W 650W 700W. is it just about how good it will be for my computer or is it about how much my computer can take?
Can someone explain me the difference betwen the "W"

 

[The_Other_One]

Wattage has very little correlation to the actual quality of the power supply. A power supply could have very high wattage but be very low quality. More specifically, it could have high wattage but low amps.

Amps are what you need to look into. Every power supply has a sticker showing its specs. You want to find a power supply with the most amps on the 12V rail(s). Something around 40 total 12 volt amps should be adequate for most computers today.

 

[kimsland]

Your volts are constant (that's what comes out of your power outlet)

Watts = Volts x Amps

Well Volts are constant, so therefore Amps must increase only

A higher Wattage Power Supply can take more Amps
And therefore does not strain as much under load (load = amps)

Your hardware pulls Amps, the Power Supply only supplies the amount of Amps your Hardware pulls (ie if it was a 1000watt power supply, your hardware will still have the same amps (and of course constan voltage)

BUT, a bigger Power Supply Wattage will not work as hard as a smaller wattage Power Supply

But (again) You should only purchase a Power Supply about 33% more that what is absolutely required, otherwise the PowerSupply will be underworked.

And that's the confusion answered