If this kind of rumors is always taken lightly, those that follow deserve yet to be given some credit.
Revealed by the site VGLeaks and times and cross-referenced with the information available to Eurogamer, the likely characteristics of the next Xbox 720 (codenamed Durango) are as follows. The heart of the console is an AMD processor with 8 eight cores clocked at 1.6 GHz and based on the architecture Jaguar. The latter was originally intended for quad-core machines but was doubled for next-gen consoles. This is the same processor as its competitor, the PS4 (codenamed Orbis).
Followed 8GB of DDR3 RAM and 32MB of "ESRAM." Operating in parallel, the two poles of memory should allow a max of 170 GB / s. Graphically, the next console Microsoft seem less powerful than Sony since it would leave on 18 computing units while the Radeon Xbox 720 does count as 12. The diagram (below) also mentions three modules, one of the goals is to compensate in software for this probable difference in power (1.23 teraflops for the Xbox 720 teraflops against 1.84 for the PS4).
On the characteristics most "basic" could count on a hard disk 500GB Sata 2.0 minimum and a 6X Blu-ray discs that supports double-layer 50 GB Ethernet port, USB 3.0 ports a Kinect connector and the presence of WiFi and WiFi Direct are also advanced.
Information to clearly conditional pending the official announcement of the two manufacturers, even if all this seems fairly plausible.