Duncan, 
thanks. Not knowing what is a quiet or noisy loop beforehand, I wouldn't like to do my programming around that theme though :-) 
By the way, does your phrase "noisy CPUs" suggest noisy types of CPU or noisy individuals of generally ok types of CPU (you might not know that, though)?
Regards, Ulrike

---------- Original Message -----------
From: Duncan Murdoch <murdoch@stats.uwo.ca> 
To: Ulrike Grömping <groemping@tfh-berlin.de> 
Cc: r-devel@r-project.org 
Sent: Mon, 15 Jan 2007 13:07:10 -0500 
Subject: Re: [Rd] Whine in dual core Windows PC if R uses full CPU capacity

> On 1/15/2007 12:02 PM, Ulrike Grömping wrote: 
> > Dear R-developers, 
> > 
> > the following may seem a weird question for R-devel [WINDOWS-1252?]– I try anyway, because it 
> > does seem to be related to usage of R and R's way of interacting with the 
> > hardware. 
> > 
> > When running R (2.4.0) on my new dual core Windows XP system (Intel Core 2 Duo 
> > E6600, Mainboard ASUS P5B, BeQuiet Power Unit), I observe various types of 
> > sounds (not related to fans) when running at full usage of at least one of the 
> > cores. 
> > 
> > The most annoying sound [WINDOWS-1252?]– a high-pitched noise like a whine [WINDOWS-1252?]– I have so far 
> > observed running simulations in R only and [WINDOWS-1252?]couldn’t reproduce with any other 
> > software (sometimes [WINDOWS-1252?]it’s also more a rustle than a whine, that one is not 
> > disturbing). I can clearly track it down to particular instances of R [WINDOWS-1252?]– as 
> > soon as I left-click on a blue window bar in the affected R-Gui, the noise 
> > stops (and there are sometimes other instances of R running in parallel which 
> > are completely unrelated to the whine). [WINDOWS-1252?]I’ve also stopped R when the computer 
> > just whined and started SAS, fully using the CPU as well [WINDOWS-1252?]– no whine. Shut down 
> > SAS, restart R à whine again. Apparently, it can also be related to what 
> > exactly R is doing at the particular moment. For example, I just discovered 
> > that simulations of one type were finished, because the computer [WINDOWS-1252?]– running 
> > another simulation under full load on R in a quiet way [WINDOWS-1252?]– started whining at 
> > the moment it switched to the new type of simulation. 
> > 
> > The hardware technician [WINDOWS-1252?]I’ve asked about this issue does not have any idea and 
> > suspects R to do something peculiar that causes the noise. [WINDOWS-1252?]It’s not the 
> > mainboards fault (that has already been changed for another reason, and the 
> > behavior remains). I [WINDOWS-1252?]can’t definitely locate the source of the sound. I 
> > suspect that [WINDOWS-1252?]it’s the Power Unit, but there are so many parts close together 
> > that I am not really sure. 
> > 
> > I do not know enough about interactions of R with hardware to know whether it 
> > is even possible for anyone deeper into the matter to develop an idea what 
> > could be behind this behavior. For the moment, I can get rid of the whine by 
> > using the mainboard tool [WINDOWS-1252?]„AI [WINDOWS-1252?]Gear“ to reduce the [WINDOWS-1252?]processor’s speed from 2.4GHz 
> > to 1.7GHz when I want to concentrate [WINDOWS-1252?]– then the whine is gone (but the 
> > simulation is slower). 
> 
> I haven't heard this from R, but on occasion I've had noisy CPUs.  I 
> suspect it's a case of some repetitive calculation leading to repetitive 
> electric fields which happen to cause physical resonance of some part of 
> your system.  That agrees with the observation that changing the speed 
> changed the noisiness.  Another way to get rid of it would be to change 
> the contents of the loop:  make it run faster or slower and the noise 
> should go away. 
> 
> Duncan Murdoch 
> 
> > 
> > Does anyone have any idea [WINDOWS-1252?]– or hints regarding what else I could think about ? 
> > 
> > Regards, Ulrike 
> > 
> > ****************************** 
> > Prof. Dr. Ulrike Grömping 
> > Fachbereich II 
> > TFH Berlin 
> > Luxemburger Str. 10 
> > 13353 Berlin 
> > mail: groemping@tfh-berlin.de 
> > www: www.tfh-berlin.de/~groemp/ 
> > ****************************** 
> > 
> > ------- End of Forwarded Message ------- 
> > 
> > ****************************** 
> > Prof. Dr. Ulrike Grömping 
> > Fachbereich II 
> > TFH Berlin 
> > Luxemburger Str. 10 
> > 13353 Berlin 
> > mail: groemping@tfh-berlin.de 
> > www: www.tfh-berlin.de/~groemp/ 
> > ****************************** 
> > 
> >   
> > 
> >     [[alternative HTML version deleted]] 
> > 
> > 
> > 
> > ------------------------------------------------------------------------ 
> > 
> > ______________________________________________ 
> > R-devel@r-project.org mailing list 
> > https://stat.ethz.ch/mailman/listinfo/r-devel 
------- End of Original Message -------
 

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