Undervolting Power Supply?

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MarkFahey

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Mar 10, 2004
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Hi Everyone,

Here is a question for you tech experts. Can a power supply that is undervolting cause any damage to PC components? If so, what would likely be damaged? CPU, Video Card, Memory, etc? If damage can result then is it possible that a component would still fuction but exibit strange anomiles like graphic or data corruption? Also would it matter how long the system was running with this situation, for example several months or would damage occur within a small amount of time?

The reason I am asking this question is because I just recently found out that my Antec True Power 550 has been running with the +12 and +5 volt rails low. The 12v rail was dipping to 11.855 and the 5v rail was dipping to 4.811.

Thanks!

Mark
 
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Dec 12, 2005
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well it wont usualy do dammage just your system might become reall unstable if you have componets that are picky about thier voltages. My enernmax whisper quiet 480w over volts the 12v big time from 12.30 to 12.65 but system runs great.
 
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Power supplies have a percent tolerance in the output voltages, the voltages your experiencing shouldn't be a concern, unless a problem with stability is happening, and really aren't out of spec.

Also, if your using the motherboards monitoring software, you probably aren't getting a true voltage reading, the only "real" way to get a true reading, is to get out a multimeter, and read the voltages from the source. I would not recommend a person who hasn't had experiences doing this to perform the reading, it's quite easy to short circuit something.
 

MarkFahey

Thread Starter
Joined
Mar 10, 2004
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Thanks for the great feedback guys!

The reason I am asking this question is that I have been experencing some strange graphics anomiles. The problem I am having is jittery, jerky, ghosting graphics not only happening on my desktop but in games as well. When I scroll through text or images in IE, Firefox, Word, etc... the movement is not smooth and is stuttering/ghosting. As well as when dragging a window across my desktop. It gets worse the faster I increase the movement or scroll. If I move the mouse super slow it is nice and smooth with no jitter but as soon as I start to speed up the movement is starts. It not only happens with the mouse but also with the keyboard arrow keys as well. So it is not mouse related.

It's similar to a Vsync tearing, but the text, image, or window has a blurring effect that is jittering or ghosting while its moving and leaves a bit of itself behind that has to catch up with itself. Where with only a Vsync tear you get the stepping tearing but not the blurring that I am getting. When I'm in a game like BF2 or Americas Army, when I turn with the mouse or strafe with the keyboard objects like trees, edges of buildings, other players, etc are ghosting and jittery where again it takes a second for the image to catch up with itself, like a graphics lag.

I just installed an nVidia eVga 6800 AGP into my ASUS P4C800-E. I am running a P4 2.4b, 2 x Corsair 512M PC3200XL's running in duel channel mode, Audigy 2, 2 x WD 120G 2mb HD's, Antec True Power-II 550W PSU, Dell 2001FP Monitor. Before this nVidia card, I was running an ATI 9700 Pro and was experiencing the same problem with that card. I did a fresh Windows XP SP2 install with this new video card, latest Intel chipset drivers, nVidia drivers and all the latest XP updates. I have also tried several older Forceware drivers.

I also tried running another OS using the Knoppix Linux 4.01 Bootable DVD version and the jitter/ghosting was even happening under Linux. So that definatly rules out any problems with Windows XP. I even moved my rig to a friends house to rule out any EMI interference I might have had at mine.

What's really weird about this issue is that my system used to run great, no graphics jitters and smooth like silk. Even when I had my ATI 9700 Pro in it. Then all of a sudden one day several weeks ago it started having this problem. I thought that it may be graphics card related, and anyway it was about time to upgrade my card so I thought that would fix it.

I have tried my rig on two other different monitors - one was a iiyama 21" CRT and the other was another Dell 2001FP. I have swapped out the Mobo for another Brand New ASUS P4C800-E, I have tried different memory, different sound card, replaced the hard drives, replaced the IDE cables, disconnected all fans and optical drives as well as replacing the PSU with a brand new Antec TP-II 550 that is running very tight on all rails.

The only other thing I haven't replaced in the CPU. Is it possible that the old PSU might have damaged the CPU? Or could an Intel processor all of a sudden start causing issues like this? Have you guys ever heard of an Intel CPU causing this kind of graphical problem?

To this point I guess I have eliminated just about everything I could think of that would cause this problem. This should not be happening, my 2D scrolling and dragging and my 3D movement in games should be smooth without jitters/ghosting. This problem really has me stumped.
 
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According to your system specs, you're overclocking that CPU. The NEXT thing you should do (since you've already done a LOT of work) is to STOP overclocking the CPU; set EVERYTHING back to normal, including RAM and CPU voltages (if you've been overvolting anything), and test the system again. Electromigration within the CPU (caused by overclocking) can CERTAINLY cause this type of problem (not good news, I realize)...

FWIW, as long as your PSU voltages are within 5% of the rated values (IOW, you get +11.4V to +12.6V on the +12V rail), your PSU is within specs. That applies across the board; all voltages within 5% indicates no actual problems with your PSU.

Since you've replaced just about everything except the CPU, that is where you need to focus your attention. Dial everything down to normal settings, and hope that the anomalies go away; if they remain, you might have permanently damaged the CPU, but let's hope not. Seeing the same problems under Linux points you directly to the HARDWARE, and you've eliminated all of the usual suspects, so the items you HAVEN'T swapped are the ones to focus on, with the CPU at the top of that list.

Good luck; keep us posted on this...
 

JohnWill

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Oct 19, 2002
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I hasten to add, that in some cases a P/S running at too low a voltage can most certainly damage things. Switching power supplies have a wide tolerance for input voltage, but when the input voltage goes down, the input current goes up. If the +12V to the processor P/S on the MB is seriously low, it may actually generate the correct voltage, but you'll be drawing a lot more input current to keep it going.
 

MarkFahey

Thread Starter
Joined
Mar 10, 2004
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13
Thanks guys for the very informative feedback once again. Sammy I was overclocking the CPU a few months ago but dialed it back down to normal even before this problem started happening. Could it be possible that the overclocking somehow damaged my CPU and that this graphic anomile wouldnt show up for a while? This graphics problem started happening about 2 moths ago and I stopped overclocking my system over 4 moths ago, so would the CPU all of a sudden start having problems after running ok for 2 months with it running back at stock speeds?

In any case, I have a new CPU on it's way. I will be replacing this P4 2.4B with a brand new P4 2.4C.

Maybe you can answer this question for me? Does the P4 2.4B 533FSB support duel channel memory mode, or is it just the 2.4C that supports it? Seeing as I am running very high quality extra low latency 2,2,2,5 Corsair PC3200XL's in duel channel I was wondering if my current 2.4B actually supports duel channel? Someone else told me that the B dosen't support duel channel but the C with its 800FSB does. Is this correct?

I was wondering if I should see a good performance increase with the 2.4C and it's 800Mhz FSB because my memory will actually run at it's rated speed of 200Mhz. Right now with the P4 2.4B 533 FSB my sticks only run at 166Mhz. Also I believe the 2.4C has Hyper Threading? I know that the 2.4B does not have this.
 
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To answer ONE question for you, it IS possible that the CPU was borderline after being overclocked, and now time, heat, and electrons have taken their insidious toll...

Now, it's time once again to reveal my personal bias...

The truth is, I have no answers to your questions about Intel CPUs; my very first CPU was an AMD 386DX-40. Yes, that represents 40 MEGAhertz; it was the FASTEST 386 CPU on the market, way back then :eek: Though I've owned SEVERAL Intel CPUs over the years, I never drank the Intel koolaid... :D

I know that when Intel introduced HT, it was ONLY available on the CPUs running at 3+ GHz, but I couldn't tell you which ones... I remember reading that HT was NOT available on the 2.8GHz CPUs, though they MIGHT have changed the fab since then to enable it at the lower speeds. I wouldn't BET on it; they charged a PREMIUM for the HT CPUs, and they'd be cutting into their own profit margins if they enabled it on cheaper / slower CPUs, though I freely admit that stranger things have happened...

For the FSB speeds, I've experimented with some of my mobile (UNLOCKED) Bartons; though I normally run them with the FSB at 200MHz or faster, I've UNDERclocked them as low as 166MHz, and I DID notice a drop in performance, along with the resulting speed improvement when I restored the 200MHz setting, but, logically, YMMV...

Hopefully, one of the Intel fanboys will be able to fill in the blanks for you; as for me, give me AMD, or give me BEER! Sam Adams Boston Lager is readily available...
 
Joined
Dec 12, 2005
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wat revison of the nVidia eVga 6800 do you have i had revison B my first 6800 i had that died was a 6800 revison A it would overclock alot and unlock pipes were the Revison B if you overclock to high on it will start blinking see ghost images. Same happens if you set the clock speed to low like at nigh time i set the card at a lower clock speed when sleeping to keep stuff running cooler if i go to slow ghost will show up all over. Also if you mess with the agp voltages it seems to cause card to act wierd.
 
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Feb 19, 2003
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It's similar to a Vsync tearing, but the text, image, or window has a blurring effect that is jittering or ghosting while its moving and leaves a bit of itself behind that has to catch up with itself. Where with only a Vsync tear you get the stepping tearing but not the blurring that I am getting. When I'm in a game like BF2 or Americas Army, when I turn with the mouse or strafe with the keyboard objects like trees, edges of buildings, other players, etc are ghosting and jittery where again it takes a second for the image to catch up with itself, like a graphics lag.
Every time I had this happen it turned out that the memory on the video card was going south. I've lost about 4 vid cards that way.

First off, try updating the drivers, then run DXdiag and see if it may be a DirectX problem. You might also try reinstalling the games.

Next, check your heat, check the fan on the card and make sure it's moving as well. Maybe try opening the case and directing a fan straight onto the card.

If it still happens, if it was me, I'd RMA the card. Normally once it starts, it just gets worse, up until the time the card becomes unuseable.
 
Joined
Dec 12, 2005
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rereading i now would say 1 of 2 things would be bad your psu or your motherboard sounds like your apg voltage is not being regulated correctly but witht the 6800 it has external molex power to so that shouldnt be that much of a deal.
 
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