This leak comes from a LinkedIn update from Daniel Mconnell, he is AMD's senior manager of System on Chip physical design. The big change is the APU changing from 28nm technology to 20nm technology.
While it's only speculation, it seems only logical that Microsoft would do something like this as Sony's Playstation 4 has quite the healthy lead in console sales.
As of right now Xbox one's processor is fabricated at 28nm which means that the transistor measures 28 thousand-millionths of a meter. If a 20nm version existed, it would lower costs , and power consumption. Since this would effect how the system cools itself, the case design could also be changed resulting in a "slim" model.
Smaller consoles also mean less packaging meaning saving costs in physically shipping units. We personally feel like $300 would be a good price point for the system here in the US, and could easily aid the Xbox One to be a better match for the Playstation 4. This of course could also lead Sony to fire back lowering there price, but my bet is that since they have sold so many consoles they will not consider a price deduction.
For more on this story , and more Xbox One news. Keep it locked to Game Rampage!