BGCH24 :
Excellent advice nukemaster and jmsellars1. I have some questions! It seems fairly necessary to get a more open chassis, in order to keep it small - but is this possible while keeping it silent?
Also: is the EVGA GeForce GTX 950 2GB SSC ACX 2.0 and other cards with similar "SSC ACX"- addons to the name tag generally smaller configurations of the (in this example) same GTX 950 chip set? will these smaller version then be less powerful?
In regards to the Metis chassis: what if i re-adjust the glass plate of the face of the chassis by about 1cm - could this substitute the lack of GPU airflow? (btw, there are these holes in the chassis opposite the window, did you think of these as reserved for the CPU cooler?)
Yeah you could easily get a quiet PC in a more open case. The more closed ones help to keep the noise in but they keep the heat in as well so the fans have to speed up anyway. The best way to go about quietness is to just design the system for quietness from the ground up in the first place rather than trying to quieten noisy components.
The best way to do that is to pick parts with low power consumption first of all, that will mean they won't generate much heat in the first place, then get the biggest heatsink you can on the CPU/GPU because heatsinks obviously dissipate the heat with no noise whatsoever then you will be relying less on fans so they won't need to spin up as much and therefore make less noise.
Then when choosing components/fans, make sure you pick those with fans that slow down/speed up based on temperature automatically. For case fans look for PWM fans that go to <500RPM minimum and for GPU/PSU you can usually find those that go down to 0 RPM minimum.
You can also minimise vibrations by avoiding optical and hard drives altogether.
That would mean overall you would have minimal vibrations, at idle the system should be completely inaudible and under load it depends on how hot your components are, how big the heatsinks are and how well the case is designed in terms of airflow.
EDIT: A high efficiency gold/platinum rated PSU is highly recommended as well because they run far cooler than bronze PSU's.
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EDIT 2: You mentioned dust resistance as well, the best way to go about that is to have a lot more air coming into the case than you have going out. That means any 'stray' air not being pushed by fans will automatically go out of the case (and take the dust with it). Then the vast majority of the dust in the case will be coming in via the intake fans and you can just put filters over them