Antec True430 power supply / low voltage on 3.3 volt rail

[Herkulese]

I have an Antec "True 430" power supply that I have been using for about 1 and 1/2 years. I had not checked the voltages for almost a year.

Recently I did a fresh install of WinXP, and downloaded the latest version of MBM. Upon checking the voltage rails, I fund the following:

+ 3.3v rail = 2.74 volts (83%) (17% low)
+ 5v rail = 4.89 volts (97.8%) (within 3% margin)
+12 v rail = 11.73 volts (97.8%) (within 3% margin)

MoBo = EPOX 8RDA (not +) Ver 1 (no official FSB 400 support)
CPU = XP-1700 TBread "A"
Ram = 512mb Crucial PC-2700

I am currently running Prime 95 stable (16 hours) as follows:
- CPU speed = 1.766gh
- FSB = 185mh
- Mult = 9.5
- Temps = (35 Idle) ( 49 Load)


This seems like a fair overclock for a "ver. 1" nF2, T-Bread "A" CPU, and PC-2700 ram, but I wonder if this low 3.3 volt rail is holding me back, and if it could cause any other problems.

Any thoughts appreciated,
Herkulese

 

[aug1516]

A multimeter would be a better way to check and would ensure more accurate results. If your 3.3 rail is in fact that low I would worry. That power supply actually quite nice and should not be running that low for any reason.

 

[Herkulese]

I assume that this would be done on the main mobo power plug.

Which leads should be tested for each of the rails, or is there a link that you can provide that would show this?

Thanks,
Herkulese

 

[LiLithTecH]

Measuring it at the Motherboard will only tell you
whether the PSU is delivering the correct Voltage,
but not under a load.

Make sure your VOM meter is able to take atleast up to 500v load
before attempting or you will surely damage it or the motherboard.

Pins 1, 2, and 11 are the +3 VDC (orange)leads on the MAIN Power connector.

Pins 4 and 5 are +3 VDC leads on the AUX Power connector (if available).

The Antec True PSU's (not the SL versions) have a rep of not being a good
source for using with TBird Athlon's, especially when coupled with a nVidia
card or chipset.

 

[Slikkster]

The Antec True PSU's (not the SL versions) have a rep of not being a good
source for using with TBird Athlon's, especially when coupled with a nVidia
card or chipset.

Is that true? Can you point me to more info about that? That's exactly my configuration, and I've been having some issues lately that could either be psu or capacitor related (or possibly ram).

I have the same PSU as the OP of this thread, coupled with a Soyo Dragon+ board , XP2100 CPU, and a Ti4600 videocard. Lately, I've been getting blue-screened at startups (various), but it will run stable once "warmed up", so to speak. I'd like to see what I need to change out, without ditching the whole setup unnecessarily.

I don't want to muddy the waters on this thread, but interested in your line about Antec True's and this config. More info if you please. Tks.

 

[LiLithTecH]

It is mostly from my experiences with it and varies others
from whom I have spoken with (vendors).

Recently had 250+ custom Tbird Athlon PC's for a Graphic
Arts Company with about 25% of them with a similair issue
as Herkulese's (low output on the 3volt rail) all with nVidia Quadro cards.

Since they still were under warranty there was no issue,
but I narrowed it down to them overheating with the Tbird
CPU's.

Placed some of those warrantied units in NEWER Throughbred
and Bartons and they do not have the issue (as of yet).

Replaced the others in the Tbirds and 10% failed right out of
the box.

Your problem does not sound PSU related.

Are you getting any STOP messages when it Blue Screens?
If so, what?

Do you have any USB devices attached?
Which Dragon + is it (K7V, KT333, KT600, etc...)?

 

[Zepper]

Yeah, I'd not worry too much unless you measure with a DVM and it's still low. Can you take a pic of the mobo (doesn't have to be high res or more than 640 pixels wide) and link to the pic for us to do a visual inspection?
.bh.

 

[Slikkster]

Yes, I have stop errors...but they are varied and I know how to research them. No usb devices. Anyway, I don't want to tie up this thread with this issue. I've got some new ram on the way (always looking ahead at future boxes). I've also been reading about failing caps on many different boards of my vintage, so will be looking closer at that. thanks.

 

[Herkulese]

LiLithTecH

You mentioned problems with the Antec True Power and the Athlon Tbird, especially with nVidia card or chipset. But that the Tbred and Bartons do not show this issue.

Can you explain the actual problem that is caused by combining thise compuntnts?
_______________________-

BTW, I am running a TBread "A", not a Tbird, but it is on an nVidia nForce 2 chipset.

 

[Herkulese]

Someone in another forum, mentioned that sometimes this can be a confusion with the vdimm voltage being displayed, rather than the vcore voltage. He also mentioned that it can be undervolted as well, so that a vdimm setting of 2.77 would be displayed as 2.74, as in my case.

I currently have my vdimm set at 2.77, so I decided to test out this theory. I set my vdimm to 2.90, and VIOLA, the 3.3 volt rail displayed 2.86 volts, the same undervolted amount as with the vdimm setting of 2.77 volts.

Mystery solved, for whatever reason, MBM is sensing the vdimm voltage rather than the vcore, and with the undervolting that is common, it seems to be accurate.

Thanks for the comments,
Herkulese

 

[Herkulese]

BTW

I checked the 3.3v rain in BIOS, and found that it is not shown there at all.

This must be why MBM shows the vdimm, because that value is shown in BIOS.

Why, would a mobo, in this day and time, not show all voltage rails in the BIOS?
Ref (EPOX - 8RDA)

O well, go figure.

At least it seems that nothing is out of speck.

 

[Zepper]

Some of the BIOS health readings (in my case it was fan speeds) on my MSI KM2M were screwed up when I first got it using BIOS 1.0. They had fixed it by BIOS v.1.2. Perhaps you need a BIOS update or perhaps no one has ever reported the problem (didn't consider it serious enough to worry about). So check your available BIOS updates and if that doesn't take care of it, report the problem to Epox.
. Of course, another possiblity is that the health chip itself is bad. In that case, I hope your mobo is still in warranty...
.bh.