Strange Fan Cool Noise

[paolo.pani]

Hi everybody and thanks for the help!
I'm suffering a the following weird problem:

when I lunch a particular software (Mathematica) a strange noise from some fan cool (I guess) starts. I don't know whether this noise comes from the cpu fan or the graphic card's one (if it exist).
The noise stops as soon as I close the Mathematica (which unfortunately I extensively use).
The noise is very very annoying, something like a whistle...

I have a Dell Studio XPS 13 (2 cpus and nvidia card) and Ubuntu 9.04. This didn't happen before with Intrepid.

Thanks,

Paolo

[paolo.pani]

A friend of mine just told me it is normal: graphic card's clock increases after you lunch some application and the whistle is actually the ordinary graphic card's fan cool..

is that right?

Thanks

[paolo.pani]

Update:
same laptop model (not the same laptop, but exactly the same model) on opensuse. No noise.
Same nvidia driver too..

[paolo.pani]

New update (although I'm actually reply to myself :) )

It is not a fan noise. The frequency is too high (around 20 kHz I guess, my mother and other over 40 people cannot perceive it).
I think it is some noise due to alimentation or electronics.

It is definitely a problem related to Ubuntu Jaunty: I tried different laptops with Ubuntu 9.04 and the problem is there, with either other distros or older Ubuntu version there is no whistle.

Could it be related to the new Xorg Server version?
It is the only thing I can imagine...