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Brand new T420s - High pitch noises when running on battery

2012-06-27, 12:00 PM

I've been using a T400 for the last 4,5 years and been very happy with it. My only complaint was high pitch noises from the CPU, especially when scrolling in a browser which seems to be an CPU intensive action. Back in 2008 when I bought it it was said this was because of how the CPU worked/was designed, so I didn't do much about it.


Honestly I was looking forward to getting a new Lenovo and I did not even think about expecting similar problems with a new one... but what do you know... when running my brand new T420s on battery the same high pitch noises crackle from the laptop.


I searched the forums and someone said to turn off the CPU Power management in BIOS, which I did, and this did reduce the noise, but it also made the computer run hotter which made the fan run 24/7, which is more noisy than anything i've encountered in a laptop in my life.


Also, whats up with the fan constantly running... I have the laptop docked, have a normal amount of desktop applications running, nothing too cpu demanding, and the fan is just constantly running...


Are my computers (old T400 and this T420s?) broken or is that high pitched noise suppose to be there? Is there anything I can do about it?




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Re: Brand new T420s - High pitch noises when running on battery

2012-06-27, 16:26 PM
It's CPU whine and is found sporadically regardless of machine. I'd try and ask for a replacement if you can.

Try undervolting the T400 with RMClock; it might reduce or remove the noise.

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Re: Brand new T420s - High pitch noises when running on battery

2012-09-27, 1:48 AM



It's called coil whine, and if it's loud enough to bother you in a power state you need to use, it's broken. People may try to tell you it's "within specification", but in certain cases, it's completely unacceptable.


I've put up with some coil whine over the years, but my T420s exhibits by far the worst case I've ever heard. It varies according to power settings, but it is audible with any combination of settings. Take a listen: http://soundcloud.com/discostrings/sets/t420s-coil-whine


I'm waiting for a response on the most effective way to have this repaired in another thread.


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T420s - High pitch noises when running on battery

2013-02-11, 23:13 PM

Don't have to change the BIOS.


If its not that bad that you have to get replacement you can try:


In Windows 7 Power option change "Processor Power Management" -> "Maximum processor state" (http://i.imgur.com/80amM.png).

Default value for this is 100% on battery, so try 70% or 80%.


I didn't notice this sound before, but once I had Maximum performance running on battery I did. When I changed it to Power saver it was gone.


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