noisy fan noise when AC - no fan when on battery???

[euro_alex_vaio]

I have a Sony Vaio Notebook - the model is VGN-TX3XP/B

The notebook is ok, but unfortunately there is a change when I connect the notebook to the AC-Power. It is not making any fan noise when on battery. With the exact same settings in AC-Power it the fan is running continously what is totally disturbing and incomprehendible because it might as well run as cool with the same settings as it does on battery mode?

What can be done about this noisy problem?

[euro_alex_vaio]

I've read that there was the need of a bios update only and the noise of the fan was gone in the AC mode.

It is funny with the same settings in Vaio Power management, the CPU temp increases still about 5 degrees C when I plug in the AC power, though I don't want this and there is no need or purpose as I don't want more performance.

Really guys, I would need some advice how I can use my vaio with the my VGN-TX3XP on AC-Power, because with the sound of the fan it is horrible.

what are your impressions? solutions?

[sunking101]

My NR21Z is the same, the fan is on all the time even if I'm just web browsing. No matter which power profile I select, the fan behaves in exactly the same manner. I would like to be able to turn the damned thing off! No other laptops make such a noise, just VAIOs.