Via Computer and Video Games, the latest issue of Britain's Xbox World magazine reveals that developers received Durango devkits last month, purportedly packing a 16-core IBM Power PC CPU and a GPU similar to AMD's Radeon HD 7000-series graphics cards.
http://www.ign.com/articles/2012/04/12/report-next-xbox-to-sport-a-16-core-cpu
I have no idea what a 7000 series graphics card can do, but if this is true 16 cores sounds un-developer friendly.