Thinkpads Forum

i absolutely love how quiet and cool t400 runs comparing to my old macbook. but due to it quietness, i notice a high pitch noise, coming from the hdd i believe. its not loud, but noticeable when the machine is nice and quiet. anyone having this issue? is this normal? can i fix it somehow? thanks

Remove the hard drive to see if the noise goes away.

Are you sure it's not the infamous penryn CPU whine you're hearing? What processor do you have?

ok i believe its the infamous cpu whine then, w/ the p8400. some suggested to turn off cpu power mgt in bios to rid the whine, but ofc that'll decrease batt life. any other way to rid the sound? thanks

I don't know how a processor can whine, mine turned out to be the AC adaptor. The pitch changes whenever I scroll the mouse wheel or do a multitude of tasks.

It's not actually the processor that makes the noise but other components on the motherboard that supply power to the CPU depending on its pwer requirements. I guess it's better described as mobo whine. I forget why there's electrical noise (probably something to do with dodgy insulation on some components), but basically there's nothing you can do about it.

I also had a whiney power brick, which Lenovo replaced, but that was a different issue in my case. My T400 has the mobo whine, which is present with or without AC power and changes depending on the power scheme. There are a few power settings that seem to make it less obvious -- higher performance schemes that keep the CPU running at constant speed rather than throttling up and down seem to help. It also seems to be louder when running on battery power, although that might be because the computer is nearer my ears and power is being managed more actively.

I also though it was the processor, that's why I ended up choosing a lower speed processor (P8400) because I was afraid of that. So that means some T400 with the same CPU speed can have the whine and some not?

from what I've read it's definitely a slightly random thing -- some laptops have it worse than others. It seems to be more of a manufacturing issue than a design issue.

I used to have a T60 and it whines badly with a T7200 cpu. Now my T400 /w p8400 never whine. Like pipspeak says, I also suspect it's from some components of mobo instead of the cpu, but I have no way to prove.

heh... I went the opposite way -- T61 with T7300 was silent and T400 with P8800 whines.