Power supply test

Hi
A friend of mine ask me a question and I have a doubt about the answer: can
he put a 400W PSU in his pc where he used to have a 250W PSU? Is there a
risk he could burn some components or is it ok? Thanks.

"Sab" wrote in message
...
Hi
A friend of mine ask me a question and I have a doubt about the answer:
can
he put a 400W PSU in his pc where he used to have a 250W PSU? Is there a
risk he could burn some components or is it ok? Thanks.



It's ok (even preferable) to use a larger-rated supply...
your machine will only draw what power it needs.

"philo" wrote in message
...

"Sab" wrote in message
...
Hi
A friend of mine ask me a question and I have a doubt about the answer:
can
he put a 400W PSU in his pc where he used to have a 250W PSU? Is there a
risk he could burn some components or is it ok? Thanks.



It's ok (even preferable) to use a larger-rated supply...
your machine will only draw what power it needs.

Or the OP could tell him with that much more power it'll make the machine
run nearly twice as fast ;-) But seriously I agree with your answer. An
advantage with using a (good quality) higher power PSU is that it will
stress it and heat it less resulting in greater PSU reliability. It will
also allow for expansion of the system (by adding more power hungry bits)
down the line.

Paul

It is perfectly safe, and a very good idea.

--
DaveW



"Sab" wrote in message
...
Hi
A friend of mine ask me a question and I have a doubt about the answer:
can
he put a 400W PSU in his pc where he used to have a 250W PSU? Is there a
risk he could burn some components or is it ok? Thanks.

Thank you everybody



"DaveW" wrote in message
news:LVPWc.84130$TI1.1744@attbi_s52...
It is perfectly safe, and a very good idea.

--
DaveW



"Sab" wrote in message
...
Hi
A friend of mine ask me a question and I have a doubt about the answer:
can
he put a 400W PSU in his pc where he used to have a 250W PSU? Is there a
risk he could burn some components or is it ok? Thanks.

The risk is that he spent all that money and the 400 watt
supply is still really only a 300 watt supply - except missing
some essential functions that were in the original 250 watt
supply that was doing just fine. How that watts is determined
is very suspect. Too many worry about watts and completely
ignore other more important functions. Recent example:
"power problems" in alt.comp.hardware.pc-homebuilt on 24 Aug
2004 at
http://tinyurl.com/4veat
And the information he claims he got from Q-Tec is shocking. I mean THIS...
Total "Real" power output [W] 300 ("Peak" Power 400)
Output current +5V [A] 25A (Sticker 30A)
+3.3V [A] 14A (Sticker 20A)
+12V [A] 12A (Sticker 16A)
Max total pwr for 3.3 and 5 combined 150 W (Sticker 180W)

The risk to computer components would be PSU functions that
are missing in that 400 watt supply and that might exist in
that 250 watt supply.

Sab wrote:
Hi
A friend of mine ask me a question and I have a doubt about
the answer: can he put a 400W PSU in his pc where he used to
have a 250W PSU? Is there a risk he could burn some components
or is it ok? Thanks.

Whats to say the old 250 Watt PSU wasn't a Q-Tec or worse? Surely you're
attempting to scaremonger with a post outlining such problems without
finding out the finer details of "what was replaced by what" (specifically)
first?

As long as the new 400 Watt PSU is reasonable quality or better, the OP will
have absolutely no problems as a result.

Paul
"w_tom" wrote in message
...
The risk is that he spent all that money and the 400 watt
supply is still really only a 300 watt supply - except missing
some essential functions that were in the original 250 watt
supply that was doing just fine. How that watts is determined
is very suspect. Too many worry about watts and completely
ignore other more important functions. Recent example:
"power problems" in alt.comp.hardware.pc-homebuilt on 24 Aug
2004 at
http://tinyurl.com/4veat
And the information he claims he got from Q-Tec is shocking. I mean
THIS...
Total "Real" power output [W] 300 ("Peak" Power 400)
Output current +5V [A] 25A (Sticker 30A)
+3.3V [A] 14A (Sticker 20A)
+12V [A] 12A (Sticker 16A)
Max total pwr for 3.3 and 5 combined 150 W (Sticker 180W)

The risk to computer components would be PSU functions that
are missing in that 400 watt supply and that might exist in
that 250 watt supply.

Sab wrote:
Hi
A friend of mine ask me a question and I have a doubt about
the answer: can he put a 400W PSU in his pc where he used to
have a 250W PSU? Is there a risk he could burn some components
or is it ok? Thanks.

Be scared when someone 'feels' more watts and only wattage
is important. A computer power supply must meet a long list
of essential specs that were even defacto standard 30 years
ago. The question is not about the original supply. The
question is where are all those essential specifications in
this so called 400 watt supply? We cannot scare people enough
when power supplies are sold without claiming to include other
and important specs. Those same specifications may hype a
wattage the supply does not output continuously.

400 watts really does not say what the power supply can
output. If it the instantaneous output power? It is really
the power consumed - which should always significantly larger
than the output power. Some brand name machines rated their
power supplies on constant output power. Therefore a 250 watt
brand name power supply is same as the 400 watt hyped to ill
informed computer assemblers.

Until it specifically claims to meet other essential
requirements, then it probably is one of those so many
inferior supplies dumped into N America that cannot even
output the wattage it claims. Why are so many inferior
supplies dumped? Because so many computer assemblers don't
even know basic electrical principles let alone understand
what those essential requirements are. Instead they buy the
'dumped' power supply only because it is cheaper. A classic
bean counter mentality.

Need more examples? Some supplies even self destructed when
a supply approached (did not obtain) its rated power. What
does one necessary and defacto standard say of power
supplies? All outputs even must be shorted together and still
the power supply is not damaged. Yes, read that again.
Supply must not be damaged even when all outputs are shorted
together. This also demanded by industry standards.

The test only asked a supply to provide its rated wattage -
and still some power supplies failed:

http://www6.tomshardware.com/howto/0...pplies-15.html
Time and time again, our lab measurements were unable to
verify the output figures represented on the model
identification sticker. And how, exactly, is a computer
purchaser supposed to check the output of a power supply?

Exactly. What really is the output wattage of that supply?
When so many 'dumped' supplies cannot even output their
claimed wattage and when some supplies even self destruct,
then what is its real wattage? The previously posted QTec
example demonstrates a common problem with supplies that do
not provide a long list of specifications. Computer
assemblers are only concerned with the one spec they
understand - dollars - and hype another using mystical
reasoning - wattage.

Be wary of advise that only discusses wattage and that fails
to discuss other, critically important functions. Most every
computer has more then enough power with a 300 watt power
supply. But this means it is really a 300 watt supply. Too
many who recommend supplies do not even know how to measure
that wattage.

Paul Murphy wrote:
Whats to say the old 250 Watt PSU wasn't a Q-Tec or worse? Surely
you're attempting to scaremonger with a post outlining such
problems without finding out the finer details of "what was
replaced by what" (specifically) first?

As long as the new 400 Watt PSU is reasonable quality or better,
the OP will have absolutely no problems as a result.

I will not be scared - not even by a Troll!

Paul
"w_tom" wrote in message
...
Be scared when someone 'feels' more watts and only wattage
is important. A computer power supply must meet a long list
snip

How nice. When Paul Murphy cannot challenge the science,
then he posts personal insults. Based upon this discussion
and another parallel discussion ("Antec power supply"), it is
apparent that Paul does not even have basic electrical
knowledge taught to first year engineering students. However
he would post as if he was technically knowledgeable. That is
until he was challenged by details and other basic science
concepts. So then he insults - as if that were science proof.

Stated with numerous examples: watts claimed by a power
supply are often deceptive if not outright lies. Some power
supplies will even self destruct before outputting full power
(an outright violation of both Intel specs and industry
standards of 30 years ago). A minimally acceptable power
supply must include other essential functions that are so
often missing on power supplies recommended by those without
basic technical knowledge. Functions that Paul neither
comprehends nor even knows exist.

Watts alone is a very bad parameter to select a power supply
especially when the manufacturer does not provide a long list
of numerical specifications - in writing. Unfortunately in
that other discussion, Paul seems to feel that evan a warranty
is sufficient science fact. Be very wary of power supplies
recommended by those who don't even have basic electrical
knowledge - ie don't know of functions that must be inside a
power supply and who then insult when exposed.

Paul Murphy wrote:
I will not be scared - not even by a Troll!

Paul
"w_tom" wrote in message
...
Be scared when someone 'feels' more watts and only wattage
is important. A computer power supply must meet a long list
of essential specs that were even defacto standard 30 years
ago. The question is not about the original supply. The
question is where are all those essential specifications in
this so called 400 watt supply? We cannot scare people
enough when power supplies are sold without claiming to
include other and important specs.
snip