We have some details about Durango’sAlpha kit and its components. Bear in mind that these “specs” aren’t final, the ones that Xbox 3/720/Next will have in its final design are bound to vary.- 8 cores (x86 CPU)
- 12 GB de RAM (8 + 4)
The Alpha kit has 12 GB of RAM, rather than the 8 GB in the final design. The extra 4 GB of RAM facilitates development of console system software.
- DirectX 11.x GPU
The Alpha kit uses a discrete graphics card similar in capability and speed to the GPU that will be included in the final design. The card does not have the ESRAM that the final design GPU will.
- 50GB Blu-ray Disk drive
- HDD, etc

Also we have a list with the components supplied with the Alpha kit.
Alpha kit includes:
- Console build into a PC box
- HDMI cable
- Ethernet cable
- Wired Controller

There also is a separate package that contains:
- A special version of the Xbox 360 Kinect Sensor
- Power cable
- USB cable
- Kinect included if negotiated

You also will need the following items that are not included in the Alpha kit.
- Keyboard
- A monitor or TV that supports a resolution of 1080p and equipped with HDMI input for video and audio, or DVI input for video only
- USB thumb drive with a memory capacity equal to or greater than 2 GB
- Mouse (optional)


The Alpha kit is intended to OS depuration/creation and to give developers a first view of the system.

http://www.vgleaks.com/whats-inside-durangos-alpha-kit/