I laugh whenever I see postings like this. I think you are being a little unrealistic (albeit naively)...
The fact is, it is *much* harder to cool these tiny boxes and, when the processor is pushed and heats up, the blower (it's not a fan!) is going to get louder while attempting to dissipate the additional heat being generated. The issue is space. There is simply not enough room inside the chassis to fit a (perhaps larger) fan that could dissipate the heat without noticeable noise. Instead, a blower must be used. The problem is that blowers are much less efficient and must spin at higher speeds to generate the same amount of airflow that a fan could generate at slower speeds. At idle temperatures, these higher speeds are not noticeable, but it doesn't take much more heat before noticeable speeds become necessary.
The air is pulled into the chassis via the side vents, travels over the board's surfaces (to cool other components) and is then pushed over the processor/chipset heatsink and exhausted out the chassis back. The only things that you could do are (a) increase the airflow by forcing air into the side vents, (b) provide cooler air at these side vents and/or (c) increase the space behind the NUC so that the dissipating air does not sit close to the NUC. Someone sometime back suggested put a large (120/140mm) fan, blowing upwards, under the NUC. This would provide cooler air at the side intake vents and also raise the NUC up off the desk surface.
Your other option is to get a replacement chassis that has no fans or blowers at all. There are multiple manufacturers - Akasa, SilverStone, etc. - and vendors - Logic Supply, Quiet PC, etc. - who sell fanless (blowerless) chassis for the NUC boards.
The only settings change that you could make is to lower the maximum clock and turbo frequencies so that the processor runs slower and generates less heat. This can be done from within BIOS Setup (Visual BIOS).
Hope this helps,
Amy, you can close this question, if that's your intent.
landgraf my intention is to make sure that you do not have any more question in regard to this matter. I did not add more information to your thread since Scott's input basically explains the cooling solutions for you, and there is also a good explanation of the air flow for this Intel® NUC Kit. However, if you would like to get more answers please let me know, I am here to help.
Then you can be sure I don't, and won't, have any more question in regard to this matter.