The Xbox One design doesn’t really differ much from its predecessor’s. However Microsoft have really pushed the limits on their latest console, while keeping in mind the very important factor of reliability. A reliable source says that the console has been designed to run continuously for 10 years.
And not only that, Microsoft have also kept in mind that while this device is designed to run for 10 years, it also needs to run silently enough, so that it is something one could keep in a living room. Its a hard combination to get right, so Microsoft went with a fairly large design which allows better heat dissipation.
Although no official specifications have been declared, the Xbox One is approximately 34x26x8cm, which a considerably larger than the 360.
Even though we got a pretty decent look at the console at E3, no one was able to get any sort of audio testing done, but developers working on the hardware claim that the console, when in its idle and relative inactive state, is entirely silent and barely lets out any heat from its vents.
Sources say that the Xbox One is expected to remain virtually silent when in standby and during media functions. And only a noticeable noise from the fan while gaming when the AMD processor is being put to use. This reduction in noise is because of two reasons- the optical drive being inactive during gameplay and a decent quality heat sink with a relatively large fan. The larger the blades, the slower they need to spin to displace air, and less rotations means less noise.