Archived from groups: microsoft.public.windowsxp.hardware (
More info?)
That is true, mean means average, so a high rated device can
still fail early, but that would likely be under warranty.
Do you mean to say that EPA numbers are not reliable (tongue
firmly in check)? Often ratings are only useful as related
to order and not magnitude. And as the old saying goes,
"Figures don't lie, but liars can figure."
BTW, when I said "forever" I should say that is relative to
the life of the computer. Age, ozone and dirt may cause
failure of the PS insulation and the fan bearings, but that
should be years of service.
--
The people think the Constitution protects their rights;
But government sees it as an obstacle to be overcome.
"Bob Willard" <BobwBSGS@TrashThis.comcast.net> wrote in
message news:OJxRqWhrEHA.1036@TK2MSFTNGP10.phx.gbl...
| Jim Macklin wrote:
|
| > A quality power supply will last forever unless damaged
by a
| > lightning strike and it is properly sized to handle the
| > load. All power supplies have a duty-cycle rating, the
| > number of Watts (amps) that can be delivered at all
times,
| > and how long they can deliver an over-load, such as
might be
| > encountered while starting up the motors. A quality
power
| > supply should be protected by fuses and or circuit
breakers
| > to prevent fires, this won't protect the computer from a
| > voltage spike, just designed to prevent fire.
| >
| > A good practice is to buy a power supply that is rated
large
| > enough so that with all the loads in the computer
considered
| > (CPU, RAM, hard drives, optical drives, PCI and AGP
slots
| > filled, cooling fans, USB and Firewire) the total loads
is
| > NOT MORE than 85% of rated capacity. That allows a
margin
| > for cooling.
| >
| > Cheap power supplies are not as robust and the ratings
given
| > are sometimes not really obtainable.
| > If your power supply is small, some companies ship
budget
| > computers with power supplies that are too small (the HP
| > 6465 I bought 5 or 6 years ago had only a 115 W PS) you
will
| > have trouble when you add more RAM and extra drives even
| > though the mobo and case have room for them. With the
6465
| > I replaced the PS by buying a new Antec case with a 250
W PS
| > and moved all the components from the HP case. Solved
the
| > problem of slow booting and unreliable CD burning. It
also
| > gave me a bigger case with more room for access to the
mobo
| > and better cooling.
| >
| > An over-sized Wattage rating does not actually use more
| > power, but it will deliver the power you need and run
cooler
| > and therefore longer than a too small PS that is working
too
| > hard.
| >
| > If you look at makers websites you can find service life
| > specs, such as MTBF (mean time between failures) and
| > duty-cycle ratings.
| >
| >
|
| All true, Jim, but a word of warning to the naive seems in
order -
| MTBF numbers are not lies, but they should be treated
skeptically,
| since MTBFs are usually calculated based on conditions
that are
| different from the typical home. Kinda like EPA car
mileage ratings.
| --
| Cheers, Bob
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