How you mount your AIO cooler to your computer case is important. An optimal mounting position not only decreases the amount of noise, but it also increases the longevity of your cooler.
In general, you want to make sure that:
Radiator mounted at the front with the tube side at the bottom
One good mounting position is to mount the radiator of the cooler at the frontal area of the case interior. The side of the radiator where the tubes connect should be at the bottom, and the pump should be mounted in a position where it is slightly lower than the top of the radiator, where air is captured.
Radiator mounted on top of the case with tubes down
One good mounting position is to place the radiator at the top of the case with the tubes pointing downwards. This ensures the pump is below the radiator and that air will sit at the top of the loop and not be sucked into the tubes.
If your case does not allow you to mount your radiator at the front of the case with the tubes down or at the top of the case, you can mount your radiator at the front of the case with the tubes up as a last resort.
If you do so, make sure that your cooler pump is mounted in a lower position than the top of your radiator. This will reduce the amount of air bubbles that enter the pump through the tubes, reducing the amount of noise made by the cooler.
