Lots of air enters through the bottom vent, which feeds the 180mm intake fan mounted at the bottom
This 12.8 ° C increase from open test bench to case with the same CPU cooler again made me question whether to place the three 120mm fans of the AiO cooler against the vents, as I was probably reducing the air flow. The hissing sound during charges from the vents told me air was coming in, but there was some resistance. So don’t do that. There is free space to mount such a cooler and fans anyway. Honestly, a big air cooler, with the help of the 180mm Air Penetrator fan at the bottom and vents above, would be my choice for the processor in this case.
As for noise levels, these will obviously vary depending on component selection, and with my little random build I measured, built with 360 AiO, “normal” motherboard fan profiles and AiO pump at full speed, approximately 32.4 dBA at idle and 39.3 dBA under load. Again, I remembered my mistake in mounting the fans on the outside of the radiator, as the fans drawing air directly through the vents at such a close distance produced a fairly loud hissing sound.
I will add that my concerns about the noise levels of the Air Penetrator fan were unfounded. Guess I remember running all three at the bottom of my Fortress FT02 at 100%, as I was boosting and overclocking my two air-cooled Radeon 5870 GPUs at the time. He behaved well here.