My Toshiba does the same thing.
<sarcasm> Best way I've found to fix it is to download this great program - shuts it right up: http://www.apple.com/itunes
I think it's just a big ol' problem with any laptop out there expected to have any kind of decent performance. My VAIO did it, my Toshiba does it, and I'm betting the 3790 will do it - although from my experience so far it won't be quite as bad. If silence is what you're looking for, the only truly silent portable computer I can recommend would be a Pocket PC due to it's lack of moving parts. If you can put up with hard drive seek noise then check out some of the tiny offerings from Sony, Dell, and Apple. But no matter what, it'll still be hot. The only reason the tiny lappies are quiet is because they don't have fans - so that heat is still gonna be there.
Unfortunately, there is currently no well-cooled (in terms of fan placement, noise, and temperature) laptop on the market today.