A shift to the x86 format means Xbox 360 discs won't be supported and backwards compatibility would be possible only through software emulation.
The AMD processor in the Xbox 720 reportedly combines "Jaguar" central processing units with graphics chips, according to one of the sources, who wished not to be named because Microsoft's plans have not yet been made public.
A Microsoft representative told GameSpot, "We do not comment on rumors or speculation. We are always thinking about what is next for our platform, but we don’t have anything further to share at this time."
Microsoft has not announced its future platform, though the company is reportedly preparing to do just that during an event on May 21. According to Windows blogger Paul Thurrott, the Xbox 720 will sell for $500 or $300 with a subscription.