Rumor: next Xbox has a core AMD, manufacturing problems
The site also explains that Microsoft would begin mass production of CPU starting from December, so have a good quantity to assemble the console and throw the whole thing in September 2013. But it seems that on this front there is some problem: the low quality of the first prototypes could put sticks in the wheels to the House in Redmond that, due to further testing and review of the production cycle, might be forced to delay the start of production.
The site says that this will slip the expected output of the console, even if we do not know by how much. If Microsoft planned to release it in September 2013, it is possible that these problems lead to retouch the date to November/December, in line with the launch of the Xbox 360.
For now we are still in the world of pure speculation: we will keep you updated.