The Xbox 1 is purposely oversized

[theprof00]

ICStats said:

The XB1 is oversized so that it can be more quiet.  Remember, the've designed the XB1 to be on all the time while you watch TV.

I can leave my XB1 on all the time inside a cabinet and it won't overheat / blast the fan. My PS4 requires a lot more air circulation otherwise the fan gets loud.

Have you ever built a computer?
You'll then know that the only reason it's whisper quiet is because of that gigantic fan. 20mm's are so silent. I only use 20's in my cases now because they are so smooth. They run a tiny bit more in energy cost, but the heat dissipation at the decibel level is unbeatable.

Furthermore, I'm not sure that open space means more quiet. I'd have to see some proof of that.