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12 volt VERY wide-spread problem

  • Power Supplies
  • Components
Last response: in Components
August 29, 2006 2:33:29 AM

Okay, I had a pretty old mobo with random new parts in it for a while. The PSU dropped the 12 volt so I had to buy a new one. This new one I had was Thermaltake, and was 480 watts. It had to power a

Gigabyte 8SI-MLH Mobo
256 MB 6800XT
1024MB of PC2700 DDR
Pentium 4 Northwood
Soundblaster Aud. 2 ZS
Maxtor 120GB EIDE HDD
CD Drive

And the 12 volt was at 11.6-7

So, I got tired of it all, and replaced EVERYTHING in my system except for the sound card.

So now it had to power a:

Asus P5ND2-SLI Mobo (with both stock and newest bios' tried)
Pentium 805D 2.66GHz (OCed to 3.06)
512MB Dual Channel DDR2 @ 667
256MB 6800XT (PCI-E unlike the previous, which was AGP)
BenQ DVD+R, -R, RW, CD etc Drive
Same sound card
Western Digital Caviar SE 320GB SataII HDD
and 3 fans (2 120mm and 1 80mm)

However, the 12 volt then dropped to 11.19!!!

So, I went to the store and picked up a 600w Seasonic PSU with 2 12v's w/ 18A max output, and 432w to those 12 v's.

STILL AT 11.19!!!

Why, even after a WHOLE SYSTEM REBUILD is the 12 volt still dropping so low!?

It's now beyond me.

Thank you for any suggestions!

More about : volt wide spread problem

August 29, 2006 2:59:34 AM

The ATX spec allows for a tolerance od either 5% or 10%, I forget which, andMost PSUs have a tolerance of 5%.

Unless its actually causing problems I wouldnt worry
August 29, 2006 1:56:00 PM

There is a tolerence of +/- 5%. If your PSU drops to 12.4 or less you may start having problems.

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August 29, 2006 10:26:13 PM

The software voltage reporting isn't that reliable. I just built my system and has the +12V voltage reported as +11.6V. So I did some research and apparently the software voltage reporting can't be relied on. In your case, the same motherboard with two different PSU gives the same voltage might be a good proof that the software reporting error. Maybe try another PSU, see how it goes?
August 29, 2006 11:21:42 PM

If the machine is working then close the voltage monitor and forget about it. You're looking for problems and you are finding them. If you really want to test it, get a good voltmeter and check it....and then if you find it low, forget about it. It's not going to hurt anything in all likelyhood, especially at that level.

Besides, something on the motherboard is monitoring that voltage. It's not purely software, there is a peice of hardware doing the measuring, and it also has a tolerance of 5 or 10 percent. The software is just reporting the reading. In otherwords, like I said, ignore it unless you are having problems.
August 30, 2006 1:43:28 PM

in accordance with the guy above you, my ASUS P5W DH Deluxe mobo is reporting 12.72V in the BIOS and with ASUS Probe 2. Should I be concerned?
August 30, 2006 1:50:11 PM

in accordance with the guy above you, my ASUS P5W DH Deluxe mobo is reporting 12.72V in the BIOS and with ASUS Probe 2. Should I be concerned?

Well that's outside of the specification...... try another PSU if there's another one available.
August 30, 2006 2:23:59 PM

in accordance with the guy above you, my ASUS P5W DH Deluxe mobo is reporting 12.72V in the BIOS and with ASUS Probe 2. Should I be concerned?

Unless you check it with a voltmeter, then no, I wouldn't be concerned. Like I said, there is something on the board that is measuring the voltage. The software isn't measuring the voltage, there is some piece of hardware measuring the voltage and then the software is reading that measurement and reporting it. The device measuring the voltage also has some tolerance....or an allowed error....just like the PS has. If the PS is high or low by 5% and the measuring device is reading +/-5%, for example, then you have the situation reading 0-10% variation.

In short.....don't worry about it. Use the monitor software as a general guide, look it from time to time, and then close it down and forget about it.

People worry wayyyy too much about this kind of thing. Lets look at it another way. The PS specification says the tolerance is +/-5%. Do you think any attached device is going to be designed to work strictly at only 11.4 - 12.6V? The answer is no. There will be plenty of slop built in. If the PS is putting out 11.4 volts and the device is strictly designed to only operate down to 11.4V before having a problem, then there isn't much room for error. There is going to be plenty of room in that voltage variaiton for proper operation of the devices, so people should stop worrying so much about these things and use those monitor programs as a general guide and not the end all and be all of proper operation.
August 30, 2006 2:31:03 PM

I think you may be reading more into this than there is.unless your system starts to blue screen or doing weird things,i would not worry about it.if there is a problem then worry about it.but as i understand it,you are doing just fine with no post or boot up sit back and relax are doing fine for now.if you truly are worried,then buy another more expensive psu.


X2 4400+@2.4