Problem in fan sapphire HD 3870

It makes a ALMOST week I installed a HD3870 and I have not had any problems until today ..
In fact, the fan starts to bottom in cyclical, while I'm in windows in idle and that the GPU is around 41-43 degrees. It is therefore a background for 3-4 seconds, then returns to normal speed, and it all about 30secondes ..

I have the latest drivers ... Do I not understand is that I did not notice when I play (about 63 degrees burn in Crysis) the fan is normally very quiet ...
Does the "CCC" ATI could have been planted?

Is there a way to control the fan speed: I thought see different forum ati tool or ati tray tools does not work with hd3870 .

For ATI the best is still to install just the drivers of the card. Utility management that goes with a rather heavy ...
You can always try to uninstall and reinstall the drivers ...
You always have concerns or is ripe for a coup?

Found that my display was not clear, I have decided to back my screen LCD 60hz instead of 75 ... and therefore, it is less work and map the temperature falls 37-41 to 43-47 against °...( in 75Hz) ...

And I noticed that this time, when the card reaches 43 °, the fan begins to turn very quickly, so that the temperature returns to 40, then decreases to speed .. and it makes it loop ...

So, in fact, I found different about the forum ... apparently, this would be the "seating plan" Fan at bios of the card would be set as ... perhaps then he flashed the card. but at this moment, where found this bios, and how flash card

You can always look for a BIOS on the side of your card manufacturer but it is rare to find .On specialized forums you can find BIOS be mode but the effect is not guaranteed .

I think my case is well ventilated; A + box with the 25cm fan on the side ...
Proc X2 3800 +: 36 ° idle, 52 in burn (with radiator and fan of origin)
GPU: 43-45 idle, 60 burn
HDD 31 and 34 °

On the one hand, a recent graphics card (and relatively powerful) to 43-45 in idle and 60 burn .
I just think that the table FAN is not terrible, and certainly not regular enough -> goes from 25% to 60% of a coup from 43 ° ...

it could come from the quality display if it is on high quality and the filters are turned on permanently, it's the GPU to work for nothing