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PSU 3.3v drops below acceptable level?

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Anonymous
a b K Overclocking
February 28, 2005 8:50:28 AM

Archived from groups: alt.comp.hardware.overclocking (More info?)

Hello all,

I have a program called pc alert 4 which monitors the boards voltage
and warns if it thinks the supply has some issues.

I ran sandra 2005 mem/cpu bandwidth test and found that, the 3.3v
drops to 2.9v and the pc alert starts to complain, can anyone points
me to the right direction please.

1) What's the use of the 3.3v lead?
2) How can I improve it ? (Except for changing the PSU as it is a
custom made SFF case...
3) My case temp is between 50 - 53 C... would that affect the current
supplied?

Thx

Kevin
Anonymous
a b K Overclocking
February 28, 2005 11:32:23 AM

Archived from groups: alt.comp.hardware.overclocking (More info?)

On Mon, 28 Feb 2005 05:50:28 -0800, Kevin Lam wrote:

> Hello all,
>
> I have a program called pc alert 4 which monitors the boards voltage
> and warns if it thinks the supply has some issues.

Do NOT blindly trust the CPU, PS and Temp monitor software readings. If
you read through previous posts on this newsgroup you will discover that
you need to take all those readings with a grain of salt.

>
> I ran sandra 2005 mem/cpu bandwidth test and found that, the 3.3v
> drops to 2.9v and the pc alert starts to complain, can anyone points
> me to the right direction please.

The only way you will REALLY know what the rail voltage is is to measure
it with a quality digital voltmeter.

>
> 1) What's the use of the 3.3v lead?

Most CPU's use this rail.

> 2) How can I improve it ? (Except for changing the PSU as it is a
> custom made SFF case...

See above before you do anything drastic.

> 3) My case temp is between 50 - 53 C... would that affect the current
> supplied?

I would suspect that those readings are not correct. If your CASE is
reading that high imagine how hot your CPU must be! It would have been
fried by now and you would have noticed instability and reboots.

Check your BIOS first to see what IT says the readings are. I Suspect your
system is reporting incorrect temps and voltages.

Larry Gagnon, A+ certified tech.
Anonymous
a b K Overclocking
February 28, 2005 5:17:45 PM

Archived from groups: alt.comp.hardware.overclocking (More info?)

A reading of 2.9 volts for the 3.3 volt rail is unacceptable; the
specifications for PC compatible power supplies call for a tolerance of +/-
3% or +/- 5%. That gives a lower limit for the 3.3 volt rail of ~ 3.2 volts
or ~ 3.14 volts.

Your case temperature is VERY high. The case temperature is usually sensed
by a thermistor on the motherboard. If it is near the on-board regulators
for the CPU the sensed temperature will be higher, but 53 C is VERY high. I
may mean that air circulation within the system case and air exchange
between the outside and inside is insufficient. It may also mean that the
power supply is not sufficiently cooled.

It is impossible to be more specific, or answer your other questions because
you haven't sufficiently described your system. Additional necessary
information would include among other things the CPU type and model, the
power rating vs. temperature of the power supply, the direction of the air
flow through the power supply, the standard to which the power supply claims
to adhere, cooling, other system components present, and ambient
temperature.

Keep in mind that the resolution of the temperature readout is less than the
number of digits reported; there is probably no real difference between a
reported 3.15 and 3.20, much less between 3.155 and 3.200. Try another
system monitor like MotherBoard Monitor and compare readings; especially
compare the readings when the case temperature is at a reasonable
temperature (say 35 C or less) to the voltagae when the case temperature is
above 50 C. Also compare the other voltages at those temperatures.

On the other hand, if you are not noticing any problems, then there may be
not reason to change things except to improve system case cooling.

--
Phil Weldon, pweldonatmindjumpdotcom
For communication,
replace "at" with the 'at sign'
replace "mindjump" with "mindspring."
replace "dot" with "."

"Kevin Lam" <sorchu_bf@hotmail.com> wrote in message
news:e9df0da0.0502280550.7e19a448@posting.google.com...
> Hello all,
>
> I have a program called pc alert 4 which monitors the boards voltage
> and warns if it thinks the supply has some issues.
>
> I ran sandra 2005 mem/cpu bandwidth test and found that, the 3.3v
> drops to 2.9v and the pc alert starts to complain, can anyone points
> me to the right direction please.
>
> 1) What's the use of the 3.3v lead?
> 2) How can I improve it ? (Except for changing the PSU as it is a
> custom made SFF case...
> 3) My case temp is between 50 - 53 C... would that affect the current
> supplied?
>
> Thx
>
> Kevin
Related resources
Anonymous
a b K Overclocking
February 28, 2005 5:17:46 PM

Archived from groups: alt.comp.hardware.overclocking (More info?)

Thank you very much phil, that's a very detail answer, My system
details are listed as requested:

Athlon 3000+
1G 3200 DDR
250W power supply
Maxtor Diamond plus 9 7200rpm
16X DVD rw
MSI MEGA 180 case

I think to answer your question about why the case is so hot, it's
because it's a SFF barebone, and I altered the system fan as suggested
by other peoplpe who are using it, it decreases the cpu temp from 56C
to 52C but increased the case temp from 43C to 51C, which after some
thoughts, i think it's not worth it, because the cpu can probably
torlerate a higher temp than, say the motherboard and harddisk...
correct me if i am wrong.

My worry is really that, what's the use of the 3.3V lead? I mean, if
it's low because the cpu is drawing power from the 5V lead which it
shares with, and the 3.3V lead is not used, then,I guess it doesn't
matter, but could you tell me what's the use of it?

I changed the fan back to how it's originally set and with 43C case
temp and 56C cpu temp, the 3.3v lead seems to provide 3.10 ~ 3.13v ,
would that be ok?

I mean my ultimate question is, would my system runs into trouble with
the dropped voltage?

Thx

Kevin

"Phil Weldon" <notdisclosed@example.com> wrote in message news:<dKFUd.2125$wy3.540@newsread3.news.atl.earthlink.net>...
> A reading of 2.9 volts for the 3.3 volt rail is unacceptable; the
> specifications for PC compatible power supplies call for a tolerance of +/-
> 3% or +/- 5%. That gives a lower limit for the 3.3 volt rail of ~ 3.2 volts
> or ~ 3.14 volts.
>
> Your case temperature is VERY high. The case temperature is usually sensed
> by a thermistor on the motherboard. If it is near the on-board regulators
> for the CPU the sensed temperature will be higher, but 53 C is VERY high. I
> may mean that air circulation within the system case and air exchange
> between the outside and inside is insufficient. It may also mean that the
> power supply is not sufficiently cooled.
>
> It is impossible to be more specific, or answer your other questions because
> you haven't sufficiently described your system. Additional necessary
> information would include among other things the CPU type and model, the
> power rating vs. temperature of the power supply, the direction of the air
> flow through the power supply, the standard to which the power supply claims
> to adhere, cooling, other system components present, and ambient
> temperature.
>
> Keep in mind that the resolution of the temperature readout is less than the
> number of digits reported; there is probably no real difference between a
> reported 3.15 and 3.20, much less between 3.155 and 3.200. Try another
> system monitor like MotherBoard Monitor and compare readings; especially
> compare the readings when the case temperature is at a reasonable
> temperature (say 35 C or less) to the voltagae when the case temperature is
> above 50 C. Also compare the other voltages at those temperatures.
>
> On the other hand, if you are not noticing any problems, then there may be
> not reason to change things except to improve system case cooling.
>
> --
> Phil Weldon, pweldonatmindjumpdotcom
> For communication,
> replace "at" with the 'at sign'
> replace "mindjump" with "mindspring."
> replace "dot" with "."
>
> "Kevin Lam" <sorchu_bf@hotmail.com> wrote in message
> news:e9df0da0.0502280550.7e19a448@posting.google.com...
> > Hello all,
> >
> > I have a program called pc alert 4 which monitors the boards voltage
> > and warns if it thinks the supply has some issues.
> >
> > I ran sandra 2005 mem/cpu bandwidth test and found that, the 3.3v
> > drops to 2.9v and the pc alert starts to complain, can anyone points
> > me to the right direction please.
> >
> > 1) What's the use of the 3.3v lead?
> > 2) How can I improve it ? (Except for changing the PSU as it is a
> > custom made SFF case...
> > 3) My case temp is between 50 - 53 C... would that affect the current
> > supplied?
> >
> > Thx
> >
> > Kevin
Anonymous
a b K Overclocking
February 28, 2005 11:34:44 PM

Archived from groups: alt.comp.hardware.overclocking (More info?)

Try to give each component it's own power lead. I got a similar problem that
was traced to my FX5900 video card sharing a molex lead with my DVD drive.
My PSU at 300w is at it's limit with my components. The FX 5900 draws a
buttload of power with it's added molex power connector.
"Kevin Lam" <sorchu_bf@hotmail.com> wrote in message
news:e9df0da0.0502280550.7e19a448@posting.google.com...
> Hello all,
>
> I have a program called pc alert 4 which monitors the boards voltage
> and warns if it thinks the supply has some issues.
>
> I ran sandra 2005 mem/cpu bandwidth test and found that, the 3.3v
> drops to 2.9v and the pc alert starts to complain, can anyone points
> me to the right direction please.
>
> 1) What's the use of the 3.3v lead?
> 2) How can I improve it ? (Except for changing the PSU as it is a
> custom made SFF case...
> 3) My case temp is between 50 - 53 C... would that affect the current
> supplied?
>
> Thx
>
> Kevin
Anonymous
a b K Overclocking
March 1, 2005 1:30:40 AM

Archived from groups: alt.comp.hardware.overclocking (More info?)

Intel Pentium 4 CPU motherboards use the + 12 volt rail for CPU power. I
believe most AMD CPU motherboards use the 3.3 volt rail.

The +12 volt rail for Intel Pentium 4 motherboards is connected by a
seperate 4-pin, square molex connector from the power supply to the
motherboard (near the DC to DC downconvertor/regulator). Intel Pentium 4
and Athlon CPU's use about the same core voltage (~ 1.5 volts). Intel
changed to the 12 volt rail because of the high power demands faster CPU's
with huge numbers of transistor. A CPU drawing 90 Watts of power needs a
current of 60 amperes at 1.5 volts. If the DC-DC conversion is supplied
from the 3.3 volt rail, that requires 90 watts/3.3 volts = ~27 amperes PLUS
another 30% or so for loses in the conversion. That requires very big
traces on the motherboard, and also means relatively higer losses from
resistance, and consequently higher heat production. The same 90 Watts at
12 volts requires only 7.5 Amperes plus another 30% or so.

Newer ATX power supplies should be specified for load sharing; the +12
volt, + 5 volt, and + 3.3 volt rails share the combined wattage for those
three rails, with up to nearly the full remaing power outpout available to
any of these rails (there is no specific limit for each of the three rails.)

Almost everything powered from the 3.3 volt rail is further regulated and/or
DC to DC downconverted before being used: the CPU in your case, the
chipset, the graphics card (unless it too has a 12 volt connection.

Again, you do have a severe heat problem, and that may also be causing your
3.3 volt sag.

Additional information that would help in diagnosis would be the ambient
room temperature, the number and size of fans, and the direction of air flow
through the fans, the type of heatsink, etc. Either range of CPU
temperature you mention is ok, but your motherboard temperature is
definately TOO HIGH.

As other people have mention, use other monitoring software to check the 3.3
volt rail, maybe even checking the voltage with a digital multimeter before
considering replacing the power supply. At any rate, the HIGH motherboard
temperature is a more pressing problem than the apparent 3.3 volt sag. And
yes, ~ 3.10 to 3.13 is still a bit low. HOWEVER, the voltage sensing
devices, the Analog to Digital hardware, and the monitoring software
combination probably mean that there is no real difference between a reading
of 3.10 and 3.13 volts (less than 1%). Again, what is the 3.3 volt rail
reading right after boot up? What is the motherboard temperature at idle?
CPU temperature at idle?


Fix your heat problem and perhaps the apparent voltage will go away.



--
Phil Weldon, pweldonatmindjumpdotcom
For communication,
replace "at" with the 'at sign'
replace "mindjump" with "mindspring."
replace "dot" with "."

"Kevin Lam" <sorchu_bf@hotmail.com> wrote in message
news:e9df0da0.0502281213.1f25ad28@posting.google.com...
> Thank you very much phil, that's a very detail answer, My system
> details are listed as requested:
>
> Athlon 3000+
> 1G 3200 DDR
> 250W power supply
> Maxtor Diamond plus 9 7200rpm
> 16X DVD rw
> MSI MEGA 180 case
>
> I think to answer your question about why the case is so hot, it's
> because it's a SFF barebone, and I altered the system fan as suggested
> by other peoplpe who are using it, it decreases the cpu temp from 56C
> to 52C but increased the case temp from 43C to 51C, which after some
> thoughts, i think it's not worth it, because the cpu can probably
> torlerate a higher temp than, say the motherboard and harddisk...
> correct me if i am wrong.
>
> My worry is really that, what's the use of the 3.3V lead? I mean, if
> it's low because the cpu is drawing power from the 5V lead which it
> shares with, and the 3.3V lead is not used, then,I guess it doesn't
> matter, but could you tell me what's the use of it?
>
> I changed the fan back to how it's originally set and with 43C case
> temp and 56C cpu temp, the 3.3v lead seems to provide 3.10 ~ 3.13v ,
> would that be ok?
>
> I mean my ultimate question is, would my system runs into trouble with
> the dropped voltage?
>
> Thx
>
> Kevin
Anonymous
a b K Overclocking
March 1, 2005 1:30:41 AM

Archived from groups: alt.comp.hardware.overclocking (More info?)

Phil Weldon wrote:

> Intel Pentium 4 CPU motherboards use the + 12 volt rail for CPU power. I
> believe most AMD CPU motherboards use the 3.3 volt rail.
>
> The +12 volt rail for Intel Pentium 4 motherboards is connected by a
> seperate 4-pin, square molex connector from the power supply to the
> motherboard (near the DC to DC downconvertor/regulator). Intel Pentium 4
> and Athlon CPU's use about the same core voltage (~ 1.5 volts). Intel
> changed to the 12 volt rail because of the high power demands faster CPU's
> with huge numbers of transistor. A CPU drawing 90 Watts of power needs a
> current of 60 amperes at 1.5 volts. If the DC-DC conversion is supplied
> from the 3.3 volt rail, that requires 90 watts/3.3 volts = ~27 amperes PLUS
> another 30% or so for loses in the conversion. That requires very big
> traces on the motherboard, and also means relatively higer losses from
> resistance, and consequently higher heat production. The same 90 Watts at
> 12 volts requires only 7.5 Amperes plus another 30% or so.
>
> Newer ATX power supplies should be specified for load sharing; the +12
> volt, + 5 volt, and + 3.3 volt rails share the combined wattage for those
> three rails, with up to nearly the full remaing power outpout available to
> any of these rails (there is no specific limit for each of the three rails.)
>
> Almost everything powered from the 3.3 volt rail is further regulated and/or
> DC to DC downconverted before being used: the CPU in your case, the
> chipset, the graphics card (unless it too has a 12 volt connection.
>
> Again, you do have a severe heat problem, and that may also be causing your
> 3.3 volt sag.
>
> Additional information that would help in diagnosis would be the ambient
> room temperature, the number and size of fans, and the direction of air flow
> through the fans, the type of heatsink, etc. Either range of CPU
> temperature you mention is ok, but your motherboard temperature is
> definately TOO HIGH.

From what I read on those things his temperatures seem rather common and
there's probably not a heck of a lot he can do about it without case mods
or changing the stock fans for higher power ones.

The cooling setup is a proprietary thing specifically for that case,
including the heatsink, which integrates into a rear housing doing double
duty as CPU heatsink and case exhaust.

Just guessing that his 'mod' was to lower CPU temp by reversing the rear
fan so it draws cool air in rather than run the warmed case air over the
heatsink. That would, of course, blow the hot CPU air into the case and
increase case temps.

It also seems that the 'big' heat problems begin when a graphics card is
used instead of the nForce built-in.

> As other people have mention, use other monitoring software to check the 3.3
> volt rail, maybe even checking the voltage with a digital multimeter before
> considering replacing the power supply. At any rate, the HIGH motherboard
> temperature is a more pressing problem than the apparent 3.3 volt sag. And
> yes, ~ 3.10 to 3.13 is still a bit low. HOWEVER, the voltage sensing
> devices, the Analog to Digital hardware, and the monitoring software
> combination probably mean that there is no real difference between a reading
> of 3.10 and 3.13 volts (less than 1%). Again, what is the 3.3 volt rail
> reading right after boot up? What is the motherboard temperature at idle?
> CPU temperature at idle?
>
>
> Fix your heat problem and perhaps the apparent voltage will go away.
>
>
>
March 1, 2005 3:27:45 AM

Archived from groups: alt.comp.hardware.overclocking (More info?)

On Mon, 28 Feb 2005 22:30:40 GMT, "Phil Weldon"
<notdisclosed@example.com> wrote:

>Intel Pentium 4 CPU motherboards use the + 12 volt rail for CPU power. I
>believe most AMD CPU motherboards use the 3.3 volt rail.

older motherboards of both CPU manufacturers used/some still use
a PSU +5V rail

BTW, is good to check with a multimeter the voltage of the orange PSU
wires (3,3V); may be that bios & software is showing wronge values or
the MOBo´s HWmon chip is damaged or bios bug ...
--
Regards , SPAJKY ®
& visit my site @ http://www.spajky.vze.com
"Tualatin OC-ed / BX-Slot1 / inaudible setup!"
E-mail AntiSpam: remove ##
Anonymous
a b K Overclocking
March 1, 2005 3:52:18 PM

Archived from groups: alt.comp.hardware.overclocking (More info?)

Thanx very much for all of your help

Just a little more info for my problem, the ambient temp (room temp?)
is about 23~25C, I turned off my heating tonight and the room temp is
about 18C
and the case temp if i turn on the computer and do nothing, is about
38~39 and the cpu is about 50C

After 30 mins with rainbow 6, it has gone up to 43C and 57C
I am writing this message with case temp 41C and cpu 53C

I think the room temp is affecting the sys quite a lot, has anyone got
any suggestions about a high rpm and low noise fan? preferably not too
expensive...

For the voltage problem, I think that it's probably caused by the
board's temp... the monitoring program doesn't complain anymore as I
change the fans direction back to how it was, which increased cpu temp
by 3C but lowered the case temp by 8C...

The voltage is constantly at 3.13... I still think it's quite low, but
dunno what to do...

Thx

Kev

"Phil Weldon" <notdisclosed@example.com> wrote in message news:<kYMUd.10452$Ba3.9224@newsread2.news.atl.earthlink.net>...
> Intel Pentium 4 CPU motherboards use the + 12 volt rail for CPU power. I
> believe most AMD CPU motherboards use the 3.3 volt rail.
>
> The +12 volt rail for Intel Pentium 4 motherboards is connected by a
> seperate 4-pin, square molex connector from the power supply to the
> motherboard (near the DC to DC downconvertor/regulator). Intel Pentium 4
> and Athlon CPU's use about the same core voltage (~ 1.5 volts). Intel
> changed to the 12 volt rail because of the high power demands faster CPU's
> with huge numbers of transistor. A CPU drawing 90 Watts of power needs a
> current of 60 amperes at 1.5 volts. If the DC-DC conversion is supplied
> from the 3.3 volt rail, that requires 90 watts/3.3 volts = ~27 amperes PLUS
> another 30% or so for loses in the conversion. That requires very big
> traces on the motherboard, and also means relatively higer losses from
> resistance, and consequently higher heat production. The same 90 Watts at
> 12 volts requires only 7.5 Amperes plus another 30% or so.
>
> Newer ATX power supplies should be specified for load sharing; the +12
> volt, + 5 volt, and + 3.3 volt rails share the combined wattage for those
> three rails, with up to nearly the full remaing power outpout available to
> any of these rails (there is no specific limit for each of the three rails.)
>
> Almost everything powered from the 3.3 volt rail is further regulated and/or
> DC to DC downconverted before being used: the CPU in your case, the
> chipset, the graphics card (unless it too has a 12 volt connection.
>
> Again, you do have a severe heat problem, and that may also be causing your
> 3.3 volt sag.
>
> Additional information that would help in diagnosis would be the ambient
> room temperature, the number and size of fans, and the direction of air flow
> through the fans, the type of heatsink, etc. Either range of CPU
> temperature you mention is ok, but your motherboard temperature is
> definately TOO HIGH.
>
> As other people have mention, use other monitoring software to check the 3.3
> volt rail, maybe even checking the voltage with a digital multimeter before
> considering replacing the power supply. At any rate, the HIGH motherboard
> temperature is a more pressing problem than the apparent 3.3 volt sag. And
> yes, ~ 3.10 to 3.13 is still a bit low. HOWEVER, the voltage sensing
> devices, the Analog to Digital hardware, and the monitoring software
> combination probably mean that there is no real difference between a reading
> of 3.10 and 3.13 volts (less than 1%). Again, what is the 3.3 volt rail
> reading right after boot up? What is the motherboard temperature at idle?
> CPU temperature at idle?
>
>
> Fix your heat problem and perhaps the apparent voltage will go away.
>
>
>
> --
> Phil Weldon, pweldonatmindjumpdotcom
> For communication,
> replace "at" with the 'at sign'
> replace "mindjump" with "mindspring."
> replace "dot" with "."
>
> "Kevin Lam" <sorchu_bf@hotmail.com> wrote in message
> news:e9df0da0.0502281213.1f25ad28@posting.google.com...
> > Thank you very much phil, that's a very detail answer, My system
> > details are listed as requested:
> >
> > Athlon 3000+
> > 1G 3200 DDR
> > 250W power supply
> > Maxtor Diamond plus 9 7200rpm
> > 16X DVD rw
> > MSI MEGA 180 case
> >
> > I think to answer your question about why the case is so hot, it's
> > because it's a SFF barebone, and I altered the system fan as suggested
> > by other peoplpe who are using it, it decreases the cpu temp from 56C
> > to 52C but increased the case temp from 43C to 51C, which after some
> > thoughts, i think it's not worth it, because the cpu can probably
> > torlerate a higher temp than, say the motherboard and harddisk...
> > correct me if i am wrong.
> >
> > My worry is really that, what's the use of the 3.3V lead? I mean, if
> > it's low because the cpu is drawing power from the 5V lead which it
> > shares with, and the 3.3V lead is not used, then,I guess it doesn't
> > matter, but could you tell me what's the use of it?
> >
> > I changed the fan back to how it's originally set and with 43C case
> > temp and 56C cpu temp, the 3.3v lead seems to provide 3.10 ~ 3.13v ,
> > would that be ok?
> >
> > I mean my ultimate question is, would my system runs into trouble with
> > the dropped voltage?
> >
> > Thx
> >
> > Kevin
Anonymous
a b K Overclocking
March 1, 2005 11:28:38 PM

Archived from groups: alt.comp.hardware.overclocking (More info?)

Kevin Lam wrote:

> Thanx very much for all of your help
>
> Just a little more info for my problem, the ambient temp (room temp?)
> is about 23~25C, I turned off my heating tonight and the room temp is
> about 18C
> and the case temp if i turn on the computer and do nothing, is about
> 38~39 and the cpu is about 50C
>
> After 30 mins with rainbow 6, it has gone up to 43C and 57C
> I am writing this message with case temp 41C and cpu 53C
>
> I think the room temp is affecting the sys quite a lot,

Of course room temperature 'affects' the system. That's your starting point
and whatever heat the computer produces gets added to it. Start at 18C, add
20C rise and you get 38C. Start at 25C, add 20C rise and you'll be at 45C.

> has anyone got
> any suggestions about a high rpm and low noise fan?

Those are, unfortunately, mutually exclusive terms. RPM causes noise.

> preferably not too
> expensive...
>
> For the voltage problem, I think that it's probably caused by the
> board's temp... the monitoring program doesn't complain anymore as I
> change the fans direction back to how it was, which increased cpu temp
> by 3C but lowered the case temp by 8C...
>
> The voltage is constantly at 3.13... I still think it's quite low, but
> dunno what to do...

The thing to do would be to get a DVM and measure it since motherboard
monitors often read the 3.3 line low.

>
> Thx
>
> Kev
Anonymous
a b K Overclocking
March 2, 2005 7:50:01 AM

Archived from groups: alt.comp.hardware.overclocking (More info?)

Generally, the faster the fan rotation, the higher the noise level.

Larger diameter, slower fans are quieter (all else being equal.)

Ball bearing fans are noiser than sleeve bearing fans (all else being
equal.)

Isolating the fan frame from the case helps (rubber grommets between the fan
frame, fastners, and case.) Some fan mounting kits have rubber inserts as
fastners.

If you have more than one mounting hole in your case add a fan. Sound
levels are specified in dB, a logrithmic scale, where two 30 dB fans
combined would sound twice as loud, and measuare a 33 dB sound level. (A
sound level of 30 dB is about that measured in a Library. See
http://home.new.rr.com/trumpetb/audio/dBexamp.html for a chart of
comparative sound levels.)

What you need is more air flow; if you don't have any additional fan holes,
then there are at least seven choices.

a. cool the air entering the system case
b. cut an additional hole and add a fan
c. add an internal fan that improves air circulation within the case (may
not help enough
d. use an adapter to replace the current fan with a larger diameter fan
e. add an additional fan in series with the original fan.
f. move to more exotic heat transfer methods, such as water circulation or
a heat pipe.
g. do nothing

So far you don't seem to have noticed any problems other than readings. For
the moment, (g.) has the advantage of being easy, free, and no louder.

--
Phil Weldon, pweldonatmindjumpdotcom
For communication,
replace "at" with the 'at sign'
replace "mindjump" with "mindspring."
replace "dot" with "."

"Kevin Lam" <sorchu_bf@hotmail.com> wrote in message
news:e9df0da0.0503011252.1dc630b@posting.google.com...
> Thanx very much for all of your help
>
> Just a little more info for my problem, the ambient temp (room temp?)
> is about 23~25C, I turned off my heating tonight and the room temp is
> about 18C
> and the case temp if i turn on the computer and do nothing, is about
> 38~39 and the cpu is about 50C
>
> After 30 mins with rainbow 6, it has gone up to 43C and 57C
> I am writing this message with case temp 41C and cpu 53C
>
> I think the room temp is affecting the sys quite a lot, has anyone got
> any suggestions about a high rpm and low noise fan? preferably not too
> expensive...
>
> For the voltage problem, I think that it's probably caused by the
> board's temp... the monitoring program doesn't complain anymore as I
> change the fans direction back to how it was, which increased cpu temp
> by 3C but lowered the case temp by 8C...
>
> The voltage is constantly at 3.13... I still think it's quite low, but
> dunno what to do...
>
> Thx
>
> Kev
>
> "Phil Weldon" <notdisclosed@example.com> wrote in message
news:<kYMUd.10452$Ba3.9224@newsread2.news.atl.earthlink.net>...
> > Intel Pentium 4 CPU motherboards use the + 12 volt rail for CPU power.
I
> > believe most AMD CPU motherboards use the 3.3 volt rail.
> >
> > The +12 volt rail for Intel Pentium 4 motherboards is connected by a
> > seperate 4-pin, square molex connector from the power supply to the
> > motherboard (near the DC to DC downconvertor/regulator). Intel Pentium
4
> > and Athlon CPU's use about the same core voltage (~ 1.5 volts). Intel
> > changed to the 12 volt rail because of the high power demands faster
CPU's
> > with huge numbers of transistor. A CPU drawing 90 Watts of power needs
a
> > current of 60 amperes at 1.5 volts. If the DC-DC conversion is supplied
> > from the 3.3 volt rail, that requires 90 watts/3.3 volts = ~27 amperes
PLUS
> > another 30% or so for loses in the conversion. That requires very big
> > traces on the motherboard, and also means relatively higer losses from
> > resistance, and consequently higher heat production. The same 90 Watts
at
> > 12 volts requires only 7.5 Amperes plus another 30% or so.
> >
> > Newer ATX power supplies should be specified for load sharing; the +12
> > volt, + 5 volt, and + 3.3 volt rails share the combined wattage for
those
> > three rails, with up to nearly the full remaing power outpout available
to
> > any of these rails (there is no specific limit for each of the three
rails.)
> >
> > Almost everything powered from the 3.3 volt rail is further regulated
and/or
> > DC to DC downconverted before being used: the CPU in your case, the
> > chipset, the graphics card (unless it too has a 12 volt connection.
> >
> > Again, you do have a severe heat problem, and that may also be causing
your
> > 3.3 volt sag.
> >
> > Additional information that would help in diagnosis would be the ambient
> > room temperature, the number and size of fans, and the direction of air
flow
> > through the fans, the type of heatsink, etc. Either range of CPU
> > temperature you mention is ok, but your motherboard temperature is
> > definately TOO HIGH.
> >
> > As other people have mention, use other monitoring software to check the
3.3
> > volt rail, maybe even checking the voltage with a digital multimeter
before
> > considering replacing the power supply. At any rate, the HIGH
motherboard
> > temperature is a more pressing problem than the apparent 3.3 volt sag.
And
> > yes, ~ 3.10 to 3.13 is still a bit low. HOWEVER, the voltage sensing
> > devices, the Analog to Digital hardware, and the monitoring software
> > combination probably mean that there is no real difference between a
reading
> > of 3.10 and 3.13 volts (less than 1%). Again, what is the 3.3 volt rail
> > reading right after boot up? What is the motherboard temperature at
idle?
> > CPU temperature at idle?
> >
> >
> > Fix your heat problem and perhaps the apparent voltage will go away.
> >
> >
> >
> > --
> > Phil Weldon, pweldonatmindjumpdotcom
> > For communication,
> > replace "at" with the 'at sign'
> > replace "mindjump" with "mindspring."
> > replace "dot" with "."
> >
> > "Kevin Lam" <sorchu_bf@hotmail.com> wrote in message
> > news:e9df0da0.0502281213.1f25ad28@posting.google.com...
> > > Thank you very much phil, that's a very detail answer, My system
> > > details are listed as requested:
> > >
> > > Athlon 3000+
> > > 1G 3200 DDR
> > > 250W power supply
> > > Maxtor Diamond plus 9 7200rpm
> > > 16X DVD rw
> > > MSI MEGA 180 case
> > >
> > > I think to answer your question about why the case is so hot, it's
> > > because it's a SFF barebone, and I altered the system fan as suggested
> > > by other peoplpe who are using it, it decreases the cpu temp from 56C
> > > to 52C but increased the case temp from 43C to 51C, which after some
> > > thoughts, i think it's not worth it, because the cpu can probably
> > > torlerate a higher temp than, say the motherboard and harddisk...
> > > correct me if i am wrong.
> > >
> > > My worry is really that, what's the use of the 3.3V lead? I mean, if
> > > it's low because the cpu is drawing power from the 5V lead which it
> > > shares with, and the 3.3V lead is not used, then,I guess it doesn't
> > > matter, but could you tell me what's the use of it?
> > >
> > > I changed the fan back to how it's originally set and with 43C case
> > > temp and 56C cpu temp, the 3.3v lead seems to provide 3.10 ~ 3.13v ,
> > > would that be ok?
> > >
> > > I mean my ultimate question is, would my system runs into trouble with
> > > the dropped voltage?
> > >
> > > Thx
> > >
> > > Kevin
March 3, 2005 4:07:08 PM

Archived from groups: alt.comp.hardware.overclocking (More info?)

> Intel Pentium 4 CPU motherboards use the + 12 volt rail for CPU power. I
> believe most AMD CPU motherboards use the 3.3 volt rail.
>
> The +12 volt rail for Intel Pentium 4 motherboards is connected by a
> seperate 4-pin, square molex connector from the power supply to the
> motherboard (near the DC to DC downconvertor/regulator). Intel Pentium 4
> and Athlon CPU's use about the same core voltage (~ 1.5 volts). Intel
> changed to the 12 volt rail because of the high power demands faster CPU's
> with huge numbers of transistor. A CPU drawing 90 Watts of power needs a
> current of 60 amperes at 1.5 volts. If the DC-DC conversion is supplied
> from the 3.3 volt rail, that requires 90 watts/3.3 volts = ~27 amperes
> PLUS
> another 30% or so for loses in the conversion. That requires very big
> traces on the motherboard, and also means relatively higer losses from
> resistance, and consequently higher heat production. The same 90 Watts at
> 12 volts requires only 7.5 Amperes plus another 30% or so.
>
> Newer ATX power supplies should be specified for load sharing; the +12
> volt, + 5 volt, and + 3.3 volt rails share the combined wattage for those
> three rails, with up to nearly the full remaing power outpout available to
> any of these rails (there is no specific limit for each of the three
> rails.)
>
> Almost everything powered from the 3.3 volt rail is further regulated
> and/or
> DC to DC downconverted before being used: the CPU in your case, the
> chipset, the graphics card (unless it too has a 12 volt connection.
>
> Again, you do have a severe heat problem, and that may also be causing
> your
> 3.3 volt sag.
>
> Additional information that would help in diagnosis would be the ambient
> room temperature, the number and size of fans, and the direction of air
> flow
> through the fans, the type of heatsink, etc. Either range of CPU
> temperature you mention is ok, but your motherboard temperature is
> definately TOO HIGH.
>
> As other people have mention, use other monitoring software to check the
> 3.3
> volt rail, maybe even checking the voltage with a digital multimeter
> before
> considering replacing the power supply. At any rate, the HIGH motherboard
> temperature is a more pressing problem than the apparent 3.3 volt sag.
> And
> yes, ~ 3.10 to 3.13 is still a bit low. HOWEVER, the voltage sensing
> devices, the Analog to Digital hardware, and the monitoring software
> combination probably mean that there is no real difference between a
> reading
> of 3.10 and 3.13 volts (less than 1%). Again, what is the 3.3 volt rail
> reading right after boot up? What is the motherboard temperature at idle?
> CPU temperature at idle?
>
>
> Fix your heat problem and perhaps the apparent voltage will go away.

The excessive heat in the machine could be making the metal connecters in
the ATX plug expand enough to make poor contact if they were a bit loos to
start with, resulting in a voltage drop. If the voltages are OK when
measured with a DMM but not in the monitoring software then perhaps heat can
be a cause. Or the PSU can't cope with the high temperature in the case.

Also consider cable routing/sleaving. I know of somebody who's ATX cable
only just plugged into the MB putting a strain on the wires and the plug at
the 3.3V end did not plug in quite enough, causing a drop in voltage. In
another case the plug was simply not pushed in far enough. Somebody else
use a cable sleeving kit on the PSU and one of the wires was not properly
pushed into the back of the plug on reassembly. In another instance, after
sleeving, a zip-tie was used to hold the sleeving in place and it placed as
close as possible to the plug, which put a strain on the wires.

While heat may be causing the PSU to drop its voltages, mechanical issues
could also be the cause as well.

Dave
!