Technically speaking,
250watt power supply indicates that the output TOTAL power will be limited
to 250watts.+/- 10%.
That includes all of the individual devices power requirements adding up to
250.
But if you notice on a power supply, it is sectioned to deliver certain
amount of power at certain voltage ranges....1.65, 12, 5.0, etc.
I may be wrong on this, but I don't think the power supplies are designed to
deliver all of their 250w at 1.65v.
I say that to emphasize that you may not be able to judge your power
requirement solely on the 250 number or the MAX.Rating.

Most of the time, it will be a good indicator as to the amount of power your
CPU will be getting (at 1.65v, 2.2v or whatever voltage)as they are
allocated with some proportion to the total rating.
AMD or Intel will require 250w, 300w supply, knowing you will have the
typical devices also (fans, scsi (1 or 2), hdd (ide), cdr(w), etc.

If you add the max.wattage rating of each component, that would also give
you what YOUR SYSTEM requires, allowing room for extra's later.

Another way would be to actually measure the voltage and current and
calculating the wattage on a fully loaded system, if you really wanted to
"just know".  But how long can you keep it "fully loaded" while you attempt
these measurements?  I don't think that is a realistic approach


>From: andre chiasson <[log in to unmask]>
>Reply-To: PCBUILD - Personal Computer Hardware discussion List
><[log in to unmask]>
>To: [log in to unmask]
>Subject: [PCBUILD] When  * 250Watt * power supply is not enough ??
>Date: Mon, 28 Jan 2002 21:57:58 -0500
>
>Hi,
>
>Is there a specific way to determine when a 250 watt power supply is not
>enough?  All the ide/scsi products inside the computer, plus cpu, fans,
>floppy drive, motherboard, need to be powered. But how can a power supply
>be
>monitored to verify it can supply the right quantity of power?  Any rules
>of
>thumb or scientific procedures?
>
>Thank you for you help!
>
>Andre Chiasson
>Quebec City
>
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>                      Bob Wright<[log in to unmask]>
>                       Drew Dunn<[log in to unmask]>


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