The Xbox One is boasting some nice guts. I'll get right to the good stuff.
Processor and graphics: as rumored, a heavily customized AMD chip that combines an eight-core CPU, a GPU tailored for DirectX 11.1 graphics and 32MB of high bandwidth embedded ESRAM memory. The 28nm chip will consume around 100 watts, which is slightly higher than current Xbox Slim and PS3, but Microsoft promises noise from the cooling fans will be "four times quieter."
System memory: a Sony-rivaling 8GB of RAM, although it'll be DDR3 instead of the PlayStation 4's GDDR5.
Audio and video: 1080p and 4K both supported; 7.1 surround sound.
Kinect: This will be bundled with the console and contain 250,000-pixel infrared depth sensor as well as a regular 720p web cam.
Storage and media: a 500GB hard drive of unknown speed plus a Blu-ray / DVD combo drive that will be used as little as possible. We're told disc-based games will be ripped to the HDD automatically.
Connectivity: HDMI 1.4 output and passthrough; a "few" USB 3.0 ports; gigabit Ethernet; plus, three separate 802.11n radios to allow the console to communicate with its controller (over a form of WiFi Direct) as well as other devices (such as perhaps other Windows-based phones and tablets) without losing its connection to the internet. At other times, two radios could be used to maintain a stronger WiFi signal. [Source]