undervolting causes cpu whine?

Does undervolting cause whine? From what I gather around forums, cpu whine is caused by low wattage cpus being used in voltage regulator circuits designed for high wattage cpus.

e.g. using intel P series cpus in motherboards designed to also cater for high end T series cpus.

From what I gather, the explanation for whine is strong vibrations of the capacitors when the cpus draw a smaller voltage. This is why whining is noticeable when cpus are in low power mode when intels speed step themselves.

From the same argument can I assume picking a P9600 or undervolting a T9550 on a motherboard designed for a wide range of cpus from p8400 to T9600 will have a higher chance of whine vs buying a laptop supporting a small range of cpus in it's customisation options (simply because it's VRM is more specialised)?

 

my old laptop was whinig only when there was a big load to cpu.

dont beleive everything,undervolting doesn't cause any whine or others things bunches of people have been doing undervolting without any problem.

just relax no problem will be caused by undervolting.

 

It SURE can casue the "CPU whine" In reality its the power components on the system board creating the noise and changing the level of power the CPU uses will absolutly affect the power components can can cause the dereaded noise just like switching speedstep states.

 

http://forum.notebookreview.com/showpost.php?p=4979407&postcount=6

 

100% incorrect. "magnetic bars"??? Please stop spreading that misinformation please.

secondly, CPUs and GPUs chips do not create any noise. Never have never will. This is common sense and has been proven 100 times.

 

I am not in a good mood right now, iGrim. Do not start with me. Please, do not start with me.

 

As long as misinformation is not spread we are cool.

 

No, we are not cool. I'm going to keep spreading "misinformation" whether you like it or not. Feel free to follow me wherever I go.

 

lol, I will

 

You honestly think you posted correct information???

 

I don't think that ^^^ directly answers the original question.

 

I'm going to ignore iGrim for the time being until he takes his grow-up pills.

moral hazard. The OP's question can be rephrased as "does 'anyvolting' cause CPU whine?" The transistors in CPU's are different in quality from the next sample and are sensitive to different voltages and currents. For example, a Pentium M can begin to resonate at say 0.7v while another can begin to resonate at 0.8v. The OP may be handling chips that tend to whine at a lower voltage. And another user may have chips that whine at higher voltages. I myself experience this with the many computers I handle. My notebook's GPU starts to subtly whine at a higher voltage while other users with the same GPU do not have this whine.

 

Never knew voltages could make a component make noise. News to me.

Any place I could look at this? For purely intellectual reasons I find it interesting.

 

this might have what you want:
http://www.youtube.com/results?search_query=cpu+whine&search_type=&aq=f

 

Simply too funny. Silicon chips dont make noise or resonate.

 

Voltage does not make components generate noise.

 

Maybe it's capacitor whine, or a coil.

 

not the capacitor, but coil sounds possible.

 

Either that or the MOSFET's. I've had a few clients complain to me about their notebooks giving an eerie screech when idling from the power supply and from the notebook itself. To this day, I still think it is either the component itself, or the MOSFET's as they are physically very close to each other on the motherboard. If I had Superman's ultra sensitive hearing, then I can probably deduce which is the culprit.

 

Guys chill, anyway I found the info on capicitors vibrating on this very forum itself. In some HP elitebook 6930p thread. I'll re-search for it tomorrow after I wake up.

But the raw deal is somebody solved his whine problem simply by isolating the VRM capicitors (not sure if inductors included). He squirted silicone all over the VRM caps and the sound was isolated. edit: found it in a bookmark, http://forum.notebookreview.com/showthread.php?t=389686
iGrim, that's your post m8. So how's the fix going and what do you make of the whine source?

But back to my original topic, what I want to know is: anyone here done undervolting on c2d and noticed whine?


I don't have c2d platform but from what I gather, manufacturers like dell/hp actively ignore bad component balancing so they can reuse motherboards for a wide range of models and save boatloads of $$. Apple is also included in the whine scandal. I don't buy new laptops every year so I'm interested in how widespread this knowledge is and what manufacturers are doing to address this cheap design philosophy, and thus avoid their crap when the time comes to spend some hard earned dough.

 

Oh and I didn't follow iGrim's thread to it's conclusion long ago when I first read it. So feel free to correct any misconceptions in this thread whether the vibrations are caused by capacitors, inductors or poor dc filtering. And do link to similar threads if you've done your own research on cpu whine.

The_Unique's theory of dirty dc on inductors is plausible is it not?

 

Most fascinating, Logarith. This is a good read.

 

Soviet Sunrise, neither a mosfet nor a CPU can cause this noise. It's caused by the DC-DC regulator only.

And the thread starter is right, it's caused by using cheaper components.
I built DC-DC converters myself (without CPU or MOSFETs ) and they also created a noise if I used cheaper components (the only important components are the coil and the capacitors), however I only experienced it at very high loads.
In my own notebook I also can hear a noise at different states of power consumption, mostly when it idles.

Undervolting the CPU can cause a CPU whine if it's not already there, but it's rare.
But ultramobile notebooks also have this noise problem. I have a ULV CPU and can hear the noise at light loads or in special conditions.
So any computer is affected.



But what can cause this noise. A MOSFET, impossible, and so a CPU, too. And come on, the frequency of the transistors inside the CPU is above 1GHz, there you hear nothing
Most of the DC-DC converters consist of a few resistors, a coil, a diode, a few capacitors and the converter IC itself. The resistors, diode and converter IC also can't produce this noise, they contain nothing which could vibrate. Capacitor, you say it, but I don't believe that something inside a capacitor can produce such a 'loud' noise.
I think it's the coil.
Those coils contain a ferrite core, around it is the wire. I just think that this ferrite core vibrates, caused by magnetic forces, which then, if it hits the copper wires produces this noise. The switching frequency used by most DC-DC converters is a few kHz, so possible that this is the culprit.
Why manufactures don't do anything again it.
Because it's difficult to solve and will cost a lot more.

 

Ah, I see now. Very interesting information, FrankTabletuser. I have learned something new today. Thank you for sharing this with us. +1 rep coming your way.

 

ferrite core probably = 'magnetic bar' from an earlier rock.

harmonic vibrations, no matter the cause, are a to find and cure.

 

Cheers Frank, all my future purchases are gonna involve going to the store and putting my ear on the laptop

+rep to u

 

http://forum.notebookreview.com/showthread.php?t=276661

Found this thread in dell forums, apparently culv cpus are less affected by whine. One workaround is to emulate culv speeds but using rmclock to chop down the ref fsb in superLFM mode. Has many other ways to damper whine as well but at cost of batt life.