The Samsung series 9 comes with a "silent mode" : when activated, the fans are stopped (at least on mine, the 15inch version, you cannot hear a thing). I just want to make sure that there is no risk of overheating. If the fan can be stopped like that, it makes me wonder why there is a fan in the first place ? I haven't found anything on the samsung website about this feature.
The silent mode will drop the fans and use passive cooling, however it will likely also use processor throttling to maintain passive heat levels.
It means that with passive cooling the system will only be able to use the processor at 100% for a short period of time before it will have to reduce the speed of the processor (and also the power going to it) to reduce heat generation until the system has cooled down.
in active cooling (the fans on) the system can dissipate the heat easier
therefore in passive cooling you can only use the processor at a high load for a short period of time.
Modern notebook CPUs run very cool, and only generate a lot of heat when they are stressed. It's very possibly that your fan will never come on during light use.
My guess is that if you use an intensive application the laptop fan will come on eventually.
You can download a programs like Prime95 to stress your CPU, and a program like CoreTemp to check temperatures.
Anything Below 80C is safe. The CPU has a safety to turn itself off when it reaches about 90C-95C.
Then fan is there to give the user the choice - some prefer a cooler keyboard to work with.
Samsung's 'silent mode' locks the processor speed to about half the advertised speed. This is how it stays cool. The fan will still turn on if required. It is completely safe to use your computer in this mode.