# Voltage drops when cpu is working



## PeepingTom

Hello
I have my q6600 overclocked to 3.00ghz on a gigabyte x38-ds4.
multiplicator x9 fsb 333
First i had it on 3,00ghz with a vcore of 1,3v. When i was watching the cpuid (everest) while stressing the system. vcore was constantly on 1,3v...Also when ideling. 
After that i set the vcore lower. On 1,275. cpuid shows me now (in idle mode) 1,264v. But when i stress the cpu it goes down to 1,232. How can this be?? 
The system is running stable with all cores on 100%, an overclock of 600mhz and a vcore raise of 0% wich even drops when busy...
Maybe everest isnt honest with me? But i set the values myself in the bios...
Whats wrong here? I thought the vcore is supposed to raise when the cpu is busy, nut the oposite...


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## 2pistolpacker

Hi PeepingTom, it's somewhat normal for the voltage to fluctuate alittle under stress. One of the first things I do is disable all thermal throttling settings, this board has a several, one called CPU thermal monitor and CPU EIST and could possibly be throttling the voltage when when the cpu heats up, try disabling both features and run your tests again. If the system shows no instability, I wouldn't worry too much about a minor voltage drop. Mike


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## PeepingTom

Hey Mike
Thanks for your answer!
You say, its normal that the voltage goes down when the cpu is used more?? This goes against all logic for me...but im willing to believe you. 
I disabled both of the two cpu settings in bios, but it didnt change. Its just strange, that when i set all to default (menas in that case: 266fsb = 2,40mhz cpu) The core voltage goes up under stress. As soon as im over fsb300 (2.70mhz) it goes down (it doesnt matter if voltage control is set to auto or to manual) ...i just dont get it. Does that mean i can set vcore even lower than it is now and it still runs on 3.0ghz?? Cause in that situation it will always go below the valu i set...nah, then its probably undervoltaging itself!? Stupid cpu!  
vcore is now on 1.275v ...means it shows me 1.264 in idle and 1.248 when all cores are on 100%
What do you think?


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## PeepingTom

Ah, just something else i wonder about: When i set System Voltage Control to "Auto", the bios sets the vcore to 1.4v automaticaly when im at 2.70ghz. and also when im @ 3.0ghz...but thats not necesary at all. Is it just prigrammed to0 do that, or is the bios reyaly relyable on such thing. I mean is it necesary to have the vcore @1.4v if the bios says so, or is the bios just speculating, that this vcore value is probably the best. I mean, the tool is called "intelligent" (m.i.t). How literary should this be taken in this case ...

Thanks for helping!!


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## 2pistolpacker

I wouldn't call it normal, but there are several factors involved, power supply fluctuations, stressed parts, ect. It's a fact some cpu's will run on less voltage than they are rated, you're lucky to find them. The way to find out how low it can go is to keep lowering the voltage until it errs out. The only readings I truly trust are what the bios tells you, since you can't monitor the bios while stress testing you're forced to rely on programs.


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## PeepingTom

Well, then i seem to be really luky and found some kind of magic Intel! ;D
It runs like this atm: 3.0ghz @ a vcore of 1.184 in idle and 1.168 under full cpu load... Unbelievable, no? I will atach a screenshot of my desktop during the stress test. Check it out if you dont believe it. 

One other thing i wanted to ask about: In the bios`s m.i.t. i have only the vcore value changed. The bios wants me to run it in auto mode, so the system voltage can be optimized. Do i have to change any othe valu in this section (system voltage control) or is it ok to simply change the vcore, and nothing else. I dont want to do damage to the board by false configuration.

Thanks again!


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## TheMatt

The readings from programs aren't always accurate. In your BIOS make sure EIST and C1E are disabled. Try different programs for Vcore readings.


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## PeepingTom

Ok, did that...besides, i already have turned of cpu eist and thermal monitor. Now i also turned off the c1e. So, cpu is not entering the c1 mode anymore...it stays constantly on 3.0ghz. But when i start stressing it, the vcore still drops (bus system runs stable). 
Bios shows me exactly the value i entered: Vcore=1.204
Everest gives a value a little lower: vcore=1.184
Speedfan is doing strange things: (same as everest)vcore 1=1.18? (shows only 2 numbers there) vocore 2=1.89 (!)

I dont know what vcore2 is, but i never set it and it acctualy doesnt seem to exist.

Also, when i start the everest cpu stress and monitor with speedfan, i can see the vcore (1) droping there as well during the stress phase.

The vcore only raises when the cpu clock is on default and system voltage control is on auto. As soon as the core is raised or the vcore is set manualy, the voltage drops under load.

Still dont have a clou what it means, but thats how it is...


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## PeepingTom

Something else that i just realized: Tu raise the vcore in bios i have to push the button with the minus sign...to lower it, the one with the plus. Its kinda upside down... Maybe it has something to do with it?


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## TheMatt

If different programs display different readings then the programs themselves aren't accurate. As long as your BIOS setting for the Vcore stays the same and your system is stable when you stress it with a program like Orthos then you are all set.


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## PeepingTom

PeepingTom said:


> Well, then i seem to be really luky and found some kind of magic Intel! ;D
> It runs like this atm: 3.0ghz @ a vcore of 1.184 in idle and 1.168 under full cpu load... Unbelievable, no? I will atach a screenshot of my desktop during the stress test. Check it out if you dont believe it.
> 
> One other thing i wanted to ask about: In the bios`s m.i.t. i have only the vcore value changed. The bios wants me to run it in auto mode, so the system voltage can be optimized. Do i have to change any othe valu in this section (system voltage control) or is it ok to simply change the vcore, and nothing else. I dont want to do damage to the board by false configuration.
> 
> Thanks again!



If someone could give an answer to this question right above, and say, that it is ok as it is, it would make me a luky man for the next 5 minutes!

Thanks for helping me


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## 2pistolpacker

It will not hurt the system to change only the cpu voltage, but if you are not having any heat or stability issues from the overclock, there really is no reason to run the voltages at anything but "auto" unless you need to raise voltage for the OC. Just keep the thermal throttling settings disabled. Mike


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## PeepingTom

2pistolpacker said:


> Just keep the thermal throttling settings disabled.



Why is that important? I have it disabled. Only thing that i left running is c1 mode.

But what you mentioned above, with auto voltage, is acctualy exactly why i posted this thread!
Well, i dont want to go any further with this, cause the system is stable and my problems as good as solved, but again:
When im on default cpu frequency and on auto voltage control in bios, the cpu goes to a vcore of 1.3v under heavy load and 1.1v when idle.

When on 3.0ghz an a manualy set vcore, it runs on 1.2v when idle and even lower when under heavy load.

Thats what i dont understand. Why the voltage is not going up anymore, as soon as i set it manualy.

The reason to not run it on auto voltage control is, that the voltage goes up to 1.4v ...wich is not necesary at all. Thats why i asked if i have to reise any other voltage as well when i raise the vcore. Kind of simulate the auto voltage setting...i dont know what voltage the auto setting raises. Does it only raise the vcore, or also other stuff? So its not necesary to raise any other voltage when raising vcore manualy?
Thats what i wanted to know.

And the funny thing is, i posted this cause i acctualy had trouble with the mainboard. It was peeping and making noise. Now, since the vcore is (+/-)stable on 1.2v, the noise it gone. Probably has something to do with the oscillation caused by low voltage...


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## 2pistolpacker

Why would you want the thermal throttling features to lower your OC after you have gone through all the trouble to manually adjust the voltages and FSB settings for your OC. The small variation in voltage from manual setting to auto is something I would have never paid any attention to. Since every custum built computer is different, how the parts interact will also be different. I only look for performance, stability and thermal issues when I OC, but tweaking the settings is part of the fun of building computers.


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## PeepingTom

Yeah, you are right...but i thought when c1 is active, the cpu still brings its full 3.0ghz when needed. And in idle it just relaxes a bit. Or is this wrong? I dont know why, but i was thinking like: less Hz=live longer ...


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## mattlock

The voltage drop is known as Vdroop and is quite normal. As for the the auto setting for voltages on the Gigabyte board, if you raise the FSB above stock then BIOS wants to handle all the voltages for you. You can ignore the "Not Optimized" warning and adjust the voltages yourself or let the BIOS handle the job. The biggest issue with AUTO voltages when OCing (as you've already pointed out) the BIOS raises the Vcore higher than needed for stable OC which obviously increases the CPU temp.

BTW, if you're concerned about CPU longivity then you really should not be OCing. C1 and EIST will adversely affect your OC stability (atleast it did on my EP35-DS3P board).


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## PeepingTom

Thx for the advice...Ill think about it. But fact is: c1 = less power consumption. Cause i dont need those 3ghz most of the time (but its nice to know, that wen needed, it runs on those 3ghz!) 
You also have to see, that i did that overclocking mainly because my mainboard was "singing" and this was the only solution to make it disapear ...now, with a raised vcore, its gone. And while i did that, i accidentaly raised the frequency of the cpu too...;D
No, seriously, thanks for all your help! 
My system is stable as it is for the moment. Also with c1 enabled...

...And thats good!


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## TheMatt

I have come across Matt's observation about the Vcore setting being auto. Whenever I OC a Gigabyte board with the Vcore voltage setting on Auto it raises it too high and the CPU then overheats. I never personally use Auto because I know if and when the Vcore should be raised.


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