explanation of voltages

  • Thread starter Thread starter Anthony Harris
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Anthony Harris

Hi, I wonder if anyone could please explain what the voltages which the
motherboards monitor means. I notice the following in the bios and my
monitoring program:

+5vsb +4.940 volt
+12V +13.050 volt
+5V +4.700 volt
+3.3V +3.200 volt
VCoreA +1.660 volt

The reason I ask is cause I want to add a 25gb HD in addition to a 80 gb and
don't want to overload the 350W power supply, which is good for a combined
220 or 250 watts I think. I don't fully understand what this means, so any
explanation will be appreciated. Thanks.

Anthony
 
Anthony Harris said:
Hi, I wonder if anyone could please explain what the voltages which the
motherboards monitor means. I notice the following in the bios and my
monitoring program:

+5vsb +4.940 volt
+12V +13.050 volt
+5V +4.700 volt
+3.3V +3.200 volt
VCoreA +1.660 volt

The reason I ask is cause I want to add a 25gb HD in addition to a 80 gb and
don't want to overload the 350W power supply, which is good for a combined
220 or 250 watts I think. I don't fully understand what this means, so any
explanation will be appreciated. Thanks.
Click to expand...

That's a good question. Different companies rate their power supplies in
different ways - some with some room built in, and some don't even do what
they claim. In addition, they might give enough power at one voltage, but
not at another. Your power supply has different voltage outputs - 12v, 5v,
and 3.3v. They don't have to be exact, but they should be close even under
load. Your numbers look OK, as long as they don't drop. It's impossible to
know if your particular HD will overload your particular power supply. Do
some searches on the web for power supply, voltage, etc. to get better
technical answers. But without a good voltage meter, you won't be able to
know for sure.
 
Hi, I wonder if anyone could please explain what the voltages which the
motherboards monitor means. I notice the following in the bios and my
monitoring program:
Click to expand...
+5V +4.700 volt
Click to expand...

this is too low if the HWmon chip is working ok ...
try another PSU & check voltages with a voltmeter & check the MoBo if
developed any bulged caps !


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& visit site - http://www.spajky.vze.com
Celly-III OC-ed,"Tualatin on BX-Slot1-MoBo!"
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this is too low if the HWmon chip is working ok ...
try another PSU & check voltages with a voltmeter & check the MoBo if
developed any bulged caps !
Click to expand...
No it isn't. +/- 10% is acceptable and it's not the +5v for the main
system board. The OP posted the +5Vsb at 4.94v
 
Conor said:
No it isn't. +/- 10% is acceptable and it's not the +5v for the main
system board. The OP posted the +5Vsb at 4.94v
Click to expand...


Just curious. Is sb standby or system board?

My +5V standby is rock solid at 4.94V, whilst at high load my +5V
(presumably system board) drops to 4.8V. So OP's 4.7V would be system board
also, yes?

meshJ
 
meshJ said:
Just curious. Is sb standby or system board?

My +5V standby is rock solid at 4.94V, whilst at high load my +5V
(presumably system board) drops to 4.8V. So OP's 4.7V would be system board
also, yes?
Click to expand...

You are correct. The +5vsb is the standby, not system board, voltage. Both
the +5v and the +5vsb are specified to be +/- 5%, not +/- 10%. If the 5.70
volts, as reported by the OP, is accurate when measured by a DVM, the OP
should investigate the reason it is out of spec. This voltage not only goes
to the motherboard and expansion boards, but also powers the electronics of
the IDE drive devices.
 
Anthony Harris said:
I notice the following in the bios and my monitoring program:

+5vsb +4.940 volt
+12V +13.050 volt
+5V +4.700 volt
+3.3V +3.200 volt
VCoreA +1.660 volt

The reason I ask is cause I want to add a 25gb HD in addition
to a 80 gb and don't want to overload the 350W power supply,
which is good for a combined 220 or 250 watts I think.
Click to expand...

What motherboard do you have, and what is its CPU speed? What video
card are you using? What brand power supply are you using (UL listing
number preferred, in case of odd make)? How many power connectors are
on the motherboard, and how many pins does each have?

The motherboard's voltage measurements can't be trusted since they're
often inaccurate by more than 5%, or the maximum tolerance allowed for
the positive voltages (not 10%). Voltage droop is a good way of
telling if a power supply is being overloaded, but you'll have to
compare readings made with the system stripped to barebones (only
motherboard, CPU, CPU cooler, keyboard, and video card installed,
preferrably a video card that doesn't draw much power) and idling to
the voltages when everything is installed and a burn-in program is
running. A change of no more than 5% is perfectly fine, while 3% is
preferred.

A good 350W supply should be fine for all but the fastest systems
because computers rarely consume more than 200-250W, but many 300W or
higher supplies won't run equipment reliably because some advertised
power ratings are fiction.

The combined power rating, assuming it's truthful, indicates the
amount of power available from the +3.3V and +5.0V outputs
simultaneously, and 220W should be more than enough since few
computers draw more than 160W combined power. But combined power is
important only for motherboards that power the CPU from the +5V output
(i.e. they have only a 20-pin and maybe also 6-pin power connectors),
and 220W should be enough for anything. However most newer
motherboards run the CPU from the +12V output (square 4-pin connector
or IDE drive power connector), in which case the combined power rating
is irrelevant and the +12V amp capacity is more important. Such
boards can draw as much as 10A form the +12V, so if less than 15A is
available you could have problems running several drives.
 
well, i had a 420w hyperpower PSU (£52UKP) with twin fan's. it lasted about
3-4month. opened it up and a few parts were burnt out. this wasnt a cheap,
low end PSU, i made sure i had the amp's where it counts.

now upgraded to an enermax 550w for 'future proofing'

i`m not running a very high load pc either.....
5.1 sfx
gf4 ti4200
overclocked 1800+tbredb 1.5v chip @ 2400mhz, 2.1vcore
a7v333/a7n8x dlx (i changed boards mid point)
512mb ram
2x maxtor ATA133 / 2x WD raptor RAID0 (recently upgraded to the RAID0,
removing maxtor drives)
liteon CD-RW 52x24x32x
DVD rom drive
fdd drive
4x 80mm case fans switch between off-7v-12v
1x 120mm watercooling radiator fan 7v-12v switched

asus probe has a default 10% margin on the 12v, 5v and 3.3v (dont list the
+5vsb)

lower power PSU's are good for (not alot :P) lower powered basic pc's with
onboard sfx, video, 1 hdd (nothing above 7200rpm) and 1 optical drive. i`d
recommend a good quality 350w+ (preferably 400w) PSU for any future upgrades
and so your not maxing out your PSU voltages.

tim
 
() |V| 3 G A said:
well, i had a 420w hyperpower PSU (£52UKP) with twin fan's. it lasted about
3-4month. opened it up and a few parts were burnt out. this wasnt a cheap,
low end PSU, i made sure i had the amp's where it counts.

now upgraded to an enermax 550w for 'future proofing'
Click to expand...

The point of the man's comments was that those figures are almost
meaningless, because there is no standard by which manufacturers can make
that claim. Tom's Hardware ran a test that showed great disparity among
claimed power and actual power. By going from a "420w" power supply to a
"550w" power supply, you might have increased your power or you might have
decreased it. Without testing, there is no way to know. It's quite a bit
more complicated than a simple number rating. There is operating
temperature (rating at low temperatures gives a much higher reading than at
hot), how the power is "split" among the different voltage rails or outputs,
etc. Some 300w supplies gave over 400w, and some 400w supplies gave 280w.
 
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