I never really understood the need for fully passive systems, who needs a PC to be that quite ? Since I went and bought AIOs for my CPU and GPU which I can run at very low RPMs I realized something quite odd, that even if the fan noise is basically gone everything else isn't, like faint electrical buzzing, coil whine or ambient noise. You'll always hear something ... unless you live in a bunker and every electrical appliance is in another room.
An important distinction when it comes to acceptable noise levels are that they are individual.
Unlike Chrispy_ I like passive cooled systems, but that is mostly for HTPC use.
I currently have 2 HTPCs one in the combined living room/kitchen. ( A8-7600 APU) This is cooled with a single 120 MM fan at ca 600 rpm, on a hyper 212. The fridge compressor is much louder than the single fan. Thing is, if it’s a quiet section in a film/series I will still hear the fan.
The second one is uses a streamcom FC8 Alpha, this system has NO moving parts, at all. This is placed in a separate TV/Hi-Fi room, which does mean that I can enjoy the complete silence when the system is running.
The MonsterLabo is actualy priced comparatively to the FC8 Alpha.
Where the FC8 has a 120W external laptop power supply with a 12V to 5V DC to DC coveter to avoid fans on the power supply, the cooling fins on that case are pretty maxed out cooling a 45W AMD 2400G.
Looking at the temperature readings for the review the MonterLabo shuld have no trouble with a similar AMD APU, or a 95W part with a better GPU. One would need a passive or semi passive PSU for that complete silence bliss.
Also note that adding a 3.5 “ HDD in a chassis like this is a bit silly, as the disk will be the loudest component by far, negating the sacrifices one makes in the quest for silent computing (the proper solution is a file server/NAS somewhere else in your dwelling)