Reports claim that Microsoft has commissioned both IBM (primary) and Global Foundries (secondary) to build a PowerPC-based System on a Chip (SoC) -- codenamed Oban -- for the next Xbox console (720/Loop/Next). The reports also claim that the 32-nm chip entered production back in December 2011, and will be available for development kits slated to arrive at game studios by April.
Rumor: Next-gen Xbox SoC "Oban," Already in Production
Xbox 720 Won't Play Used Games; Wii U Better Than X360
Source: Toms Guide