7800 GT Noise on bootup?

Just built my friend a new PC, and pre graphics card driver installation in Windows, and anywhere else where nvidia drivers werent loaded, the Asus 7800GT was very loud.

I set out to get to the root of this problem, and after installing nvidia drivers rather than the default Windows ones, the noise (I presume caused by high fan rpm) went away. After a reboot and as Windows loads back up, the fan spins up horribly fast again, but as soon as Windows loads at the logon screen it slows down.

From this, I have deduced that its obviously a driver controlled fan speed. However the guy I'm building the PC for mentioned something about over-voltage to the PCI-Express slot. While I know nothing about electronics, it seems too much of a coincedence to me for it to stop revving so much during the driver installation and as soon as Windows loads.

Can someone confirm, or lead me in the right direction to what is going on here?

Cheers

Tobe

Its fine :)
If the drivers are not loaded, it will spin at full as thats its "fail safe" - it makes sure the card dont burn up.

I have a 7800gt and it spins up, but in a few seconds it slows down again. It'sfine.

They all do the same. It is a design decision and not a fault.

Thats what I thought, but this guy wouldn't have it :P Oh well, atleast I have proof now, thanks :D