Another power supply question!

[Jonty]

I've read with interest the various questions and answers to power supply problems and recommendations and would like to know what exactly my power supply can handle.

The exact words on the supply are:

PW-200ATX Power Win switching power supply +3.3v & +5v max output 125w all output is extend to 200w max.

Now, is my supply a 125watt or 200watt? It says max output 125w but what is this 'extend to 200w max' all about. If it can give 200watts why don't they just say max 200watt??????

[qball]

Confusing heh?

Your power supply has two different circuits. One is 3.3 and the other 5 volt. You will noticed there are two power cables with multiple connectors coming out of the supply. Anyway, max on each circuit is 125 watts. Max of both circuits is 200w.

Easy.

[Jonty]

Confusing? Just a tad!

Have I understood this right? Indeed, coming out the power supply is a bunch of wires going to the mobo and then three sets going to the various drives. Are you saying that the mobo is being supplied with 125w and the drives etc with another 125w, there being a limit overall of 200w?

So as long as the mobo doesn't draw more than about 100w and the drives about 100w too everything should be OK?!

[tonym]

The 125 Watts listed is the maximum power that can be taken from the combination of the +5 *and* the +3.3V outputs. This leaves 200-125=75 Watts for the +12/-12 and -5V outputs.

The reason this occurs is that the +5 and +3.3V outputs are derived from the same internal circuitry, which is capabable of supplying 125 Watts. This is a legacy issue that provides 3.3V power for ATX style mobos from an essentially AT style (with the addition of a 3.3V switching "mag-amp" regulator).

This is one of the critical reasons that care must be exercised when using just any old power suopply for an Athlon mobo. You've got to make sure that the +5/+3.3V outputs are capable of providing adequate power when both are loaded!

Tony