CPU noise when running on battery

Hi,

I know it's been discussed on this forum ( http://forum.notebookreview.com/showthread.php?t=81668) as well as on http://forum.thinkpads.com/. This article also describes the problem and gives some suggestions for Linux: http://thinkwiki.org/wiki/Problem_with_high_pitch_noises

The reason I'm posting is because so far I haven't found any good solution to this problem. My Z61t makes a quite audible "electric" buzz/hum when running on battery. When I put my finger on the touchpad or the pointstick, the noise worsens. When a cpu-intensive task is performed, the noise subsides. There's no noise when running on AC power. I tried disabling the power management for cpu in BIOS and that does get rid of the problem at the price of considerably shorter battery life. BTW, I'm running the latest BIOS. I also tried this suggestion http://forum.tabletpcreview.com/showthread.php?t=3516. It has pretty much the same effect as disabling cpu power management - muffles the noise at the price of battery life.

I am wondering if anybody else is having the same problem? If yes, how do you deal with it? If nobody else has this, maybe my Z61t is just defective? Does it make sense to go through the hassle of dealing with Lenovo support? I've read somewhere that this problem is common for Core Duos - it that true?

Any suggestions are appreciated!
Thanks!

 

I noticed a similar high pitched sound sometimes coming from the processor area of my T60 which has a 7200. I haven't bothered to find a fix yet though.

 

My T60 has it, and almost all centrino laptops have it in some degree. Units with dedicated graphics cards seem to have it louder, as I have never had a intel GMA laptop make the noise. One thing to lessen it is to disable the cpu and pci buss power management in the bios under power settings.