Antec EarthWatts 380: 12V line @12,39V too high?

arga · Post by **arga** » Fri Jan 05, 2007 8:08 pm

Hello:

I have bought the Antec EarthWatts 380, and I have a little problem.
The 12 V rail is giving me what I think it is a very high voltage: 12,39V.
This is 3,25% above 12V.

*I think* the EarthWatts380 specsheet says it shoud be between +-3%
http://www.antec.com/specs/EA380_spe.html
(load regulation=+-3%, not sure what it means)

The ATX specification mandates +-5%, so I am still inside.

But the review here at SPCR of the E.W. 430 says that the voltages were very close to nominal (12V within 1% of the nominal value):
http://www.silentpcreview.com/article684-page4.html

Maybe my unit is defective? should I return it for another one?

winguy · Post by **winguy** » Fri Jan 05, 2007 8:24 pm

If it is a constant 12.39V and you measured that using a multimeter (and you're sure the multimeter is working as it should), then yeah it isn't operating within specifications.

arga · Post by **arga** » Sat Jan 06, 2007 5:50 am

yes, I used a multimeter, well, in fact I used 2 multimeters (both the same brand and model though) and I got the same reading.
and yes, the value is quite stable.

It would be great if I could find anyone else with the same PSU, and tells me the 12V measure.

arga · Post by **arga** » Sat Jan 06, 2007 10:19 am

urg. I have increased the load (connected a few more things)
and now the voltage it even higher: 12,43V.
while booting, it reached 12,48V.
this is clearly out of Antec's own spec of +-3% line regulation.
still, this system is not drawing too much power. so I wonder what will happen in high-power system.

update: when the CPU is at 100% load, the voltage is 12,49Volts stable (not peak).

my CPU is a XP 2500+ Barton
card: radeon 9200
now 6 HDDs connected.

jaganath · Post by **jaganath** » Sat Jan 06, 2007 11:39 am

Don't the socket A CPU's draw most of their power from the +5V and +3.3V rails? So maybe high 12V is not so bad?

qviri · Post by **qviri** » Sat Jan 06, 2007 11:57 am

jaganath wrote:Don't the socket A CPU's draw most of their power from the +5V and +3.3V rails?

Depends on the motherboard, but that could be the reason. I'd have thought that the six HDs would balance the load a little bit, though.

arga · Post by **arga** » Sat Jan 06, 2007 1:11 pm

so maybe its that I am drawing too little power from the 12V line??
or too much from the others?
mmmh.

okay, for better comparison, I have removed a couple of TV cards that I had connected.
Now it is just the CPU, the Radeon, and the HDs.

With 2 HDs:
12.40V no CPU load
12.48V full CPU load (Prime 95)

With 6 HDs:
same results.

Now, underclocking the CPU from 166FSB to 100 FSB:
12.36 V no CPU load
12.41 V full CPU load (Prime 95)

So, the more power the CPU draws, the higher the voltage on the 12V line.
But connecting more HDs have no effect.

So it seems that the Athlon XP unbalances this PSU, and its not possible to balance it with other components???

SnooP · Post by **SnooP** » Sun Jan 07, 2007 6:10 pm

No not really, if your worried get an athlonxp motherboard which has a 'P4' 4pin connector, that way the cpu will power off the 12V rail instead. Still as long as its within ATX spec which it is i don't see any reason to worry.

arga · Post by **arga** » Tue Jan 09, 2007 8:15 am

Hi again.
Maybe its not a big problem after all.
I have tested the EarthWatts on an old Celeron 1GHz system, and
voltage is 12,41V at full load.
This is better than the PSU that I had on this system (a cheap
"ANS"-branded PSU), which reaches 12,52 V at full load.

The Celeron system works ok with the Earthwatts.

@Snoop:
well, no, I am not going to buy another Socket A mobo.
I think I will use the Earthwatts in a newer computer, and hopefully
there will be more load in the 12V rail, and the voltages will be lower.