power supply

I am on the verge of bulding a media center, but a bit worried about the power supply. since this thing is going to on a lot, I was thinking of getting the samllest power supply I can. But thinking back I am sure that it don't matter if the power supply is 500watts, it only uses those 500 watts if it needs to, am I correct on that? Not that I would put 500watts in, I am looking at about 350, the machine will have 2 hard drives, once DVd writer and either a sempron AM2 or a Athlon 64 AM2. Not going for x2 core, becuase it will not be needed, unless the price comes down a bit more by next year.

Thanks

Unless things have changed a 500w psu will always use that regardless the power needed by any attached devices.

If you are planning to use 350, then I would choose a 400W just to be on the safe side.


anyone??

So if a 500W PSU is being used to supply 10W to a circuit you would have a 490W heater in the case?

yupp.

I could be wrong as I haven't plugged a PSU to any multimeter. But this is often the case.

You're wrong. My Athlon 4200+ Dual Core processor PC with its 600W power supply consumes 115W on "tickover" (measured using a meter). The whole point of switched-mode PSU's is that they are extremely efficient, and consume barely more than they are delivering. Using a power supply which is rated higher than its load often means that it will run cooler and quieter.

Edited by deleted (Fri 24-Nov-06 15:37:49)

Fair enough.

Looks like things have changed.

Thanks for the replies people. I had this feeling that power supplies only took what they needed, so it wouldnot matter if I had a 600 watt power supply, it would not take any more than a 350, unless the computer needed it? Not that I would need a 600 watt power supply.

Like my CPU have a cool and quiet function on it and also uses less power when it is not being used to it full potential, which would seem a waste if power supplies still used the same amount of power. I think a 350watt may be enough as the machine is not going to do much, Now I need to find a media/desktop case which don't cost a bomb and can take a full size ATX board.


I know some cases are cheap but they look plain, I want a bit of style as it will be put into the sitting room under theT.V

Look for a new generation 80%+ efficient PSU. It will become the new ratified standard soon anyway. (or even better 85%+).

http://www.silentpcreview.com/article28-page4.html (scroll to paragraph 'correct PSU sizing for best energy efficiency'
http://www.extreme.outervision.com/psucalculator.jsp

/strokes his seasonic M12 500w fondly

Edited by deleted (Fri 24-Nov-06 23:04:44)

Anyone interested in the power consumption of their household appliances should visit their local Maplin store (or mail order) and get a "Plug-In Mains Power & Energy Monitor ", Maplin part number L61AQ, price

Edited by deleted (Sat 25-Nov-06 09:17:34)