Hi everyone, I have just noticed that in my bios that my CPU Vcore voltage moves up & down from 1.416 - 1.424 volts, with OC 1.544 - 1.552 volts. Also it seems to move from Vcore voltage to my +3.3 rail, but doesn't show any of this in Speed Fan. My bios lately has seemed slow and flickering as the RPMS are changing. I guess the good thing is my voltage isn't dropping below my setting in bios for Vcore or any of my rails, but rather moves up in voltage rather than down.

This all started when I got my 8800GTX after getting rid of my 7800GTX that only needed one 6Pin PCI-Express connector. I don't have another graphics card to try and all my friends are still using AGP. My PSU has two PCI-E plug-ins in red color, one says master the other says slave. I havent had any stability problems yet so that might be a good sign.

Do you guys think that my PSU is detecting that its needs to up the voltages because of my 8800GTX power sucking card that it is needs more wattage? I am running Orthos Blend priority 8 on my OC in my sig, so far its ok. My spec's are in my sig.



By systemlord at 2007-11-13

Strange that the BIOS is slow and flickering as the RPMs change. Like you said, it's a good sign that you are not experiencing any stability issues. It might be that the power supply is compensating for the extra power requirements of your beast of a graphics card. :-)

You think the motherboard's voltage regulators might have anything to do with it? Just a guess. I might be completely on the wrong track.

I just failed Orthos after 6 hours, plus my +3.3v rail is 3.280 which I don't know if its ok being that low. Wonder if my mobo or PSU thats bad, one thing is for sure is there is some voltage regulation problem. Theres only two things it could be and thats my mobo or power supply.

****UPDATE****

I just remembered something, when I began my overclocking experience everytime I had to flick that on/off switch on back of the PSU it would beep loud four times everytime like its suppose to and it doesn't do that anymore. Damn Enermax is supposed to be the best, I guess I'll have to RMA it the day I get Crysis. Anyone know if the +3.3 volt rail is supposed to drop below 3.3 volts?

I've found a table for voltage tolerances on ATX power supplies. And there is an + or - 5% tolerance on the 3.3V rail. Your reading is within that limit.

Now my 5V rail is fluctuating as well, so I went into the bios and upped the Vcore, Northbridge Vcore, FSB volts and then the 3.3v rail, 5v rail and my Vcore were acting up again. The fact that this all started when I upgraded to a more power hungry graphics card tells us what? It seems the more voltage I ask for the more I see the fluctuations.

Poor PSU can't keep up!

Here's the load tests from johnnyguru, it show's the minor fluctuations in the rails.
http://www.jonnyguru.com/review_de [...] page_num=3

That's a top flight PSU, and you certainly aren't loading it up. Before I blamed it, I would get a good DVM and measure a spare MOLEX while it is under load. I would be more inclined to suspect the mobo as cfvh600 said early on.

You think because I untroduced a new component (from 7800GTX to 8800GTX) to my system that that might make my preveus overclock no longer stable? When I got my 8800GTX thats when this all started. But my CPU Vcore shouldn't move up and down should it? Maybe the rails but not CPU Vcore fluctuation, right?

Maybe try a default BIOS and see if your problems go away. I wouldn't think that would cause your voltages to fluctuate. That is a pretty high OC maybe your board got tired. I still think you should measure the power at the MOLEX connector. That would rule out the PSU

I currently have 10 hours on Orthos blend everything at stock clock with no overclocks at all. I looked at that link you gave me DellUser1 about the Enermax 720W that I have and is well within spec. Is it normal for any Vcore voltage to flucuate between 1.544v to 1.552, maybe its upping the volts to compensate for the added power draw from my 8800GTX.

Because of this extra power draw (8800GTX) do you think that when you start adding more power hungry parts to you PC that might make an otherwise stable OC unstable?

I don't know if it's normal, but after reading this thread I have been watching my Vcore with more interest today. Seems mine fluctuates between 1.28 and 1.296 ( twice the amount of yours ).
I suppose adding power hungry hardware could have an effect on the oc, but with a quality psu such as yours, I would think there would be no problems due to it.

There must be an effect on my OC because I'm still running Orthos for 16 hours now with no errors at stock clocks. Anybody else have any opinion on how this might be possible, losing an OC because of new hardware?

ALso, like cfvh600 said, All PSU's have a tolerance rating. Most are +/- 5%. I calculated your 3.3V tolerance and it was -0.6%. Thats a good tolerance IMO.

To calculate tolerance (same calculation as % error)= ((New - Original)/ Original) X 100

% Error= ((Measured - Theoretical )/Theoretical) X 100

Whenever you OC, you are stressing the system, so by adding that card, you stress it more because the card requires more power. You will probaly lose the OC, but you do not have to be at stock. If it is not stable at 3.7Ghz, step it down a few Mhz until it is stable.

Also, check the caps on your motherboard to make sure they are still fine. If your PSU is out of warranty, open it up to check the caps (or if you don't care about the warranty, open it up).

For pics about what a "bad" cap looks like go here:
http://www.badcaps.net/

I have already checked all mobo components and nothing looks burned or discolored. Would you recommend any good monitoring software for reading voltage? I tend to agree that whenever you enter something new to a perfectly stable system that its very possible that the added hardware might change things and overclocks a tad because now more power is being fed to the system which can change things ever so slightly, enough to give just an error but not a stability problem which isn't the case.

One error in 6 hours is very small, I'll just back off a little on my OC and see what happens. If I had any component to guess is to blame for this I'd have to say it has something to do with my mobo voltage regulaters, they have tolerances to.

Anyone care to add your view on this?

I tend to agree with you on the mobo regulators being the culprit, you have stressed them a bit. The DVM would rule out the PSU. They are not that expensive for a cheap one, and they are good to have around the house.

A digital volt metter? How do I know where to point those sharp pins? Also would a DVM show me all the rails and not just the 12 volt rails? Hay guys 21 hours without any errors, think I'll wait till 24 hours.