We know for sure an Xbox 360 successor is coming, but that's about it. The codename, the features, the specs – everything about the hardware itself is a big unknown at this point. But a new rumor from MS Nerd, who usually has the inside scoop on all things Microsoft, has leaked some new details that could shed some light as to what the next Xbox is all about.
It's not called the Xbox "Next" as previously reported. It's currently codenamed Xbox "Loop" and runs on a modified Windows 9 core. The hardware will be a "Zune HD-like" platform with a main processer, as well as "mulitple assistive cores" for things like graphics, AI, physics, sound, networking, and more.
It'll be much smaller that the current Xbox 360, and they're aiming for it to be cheaper, too, to further encourage Kinect adoption
These details lead me to believe that the next Xbox is currently in the very early stages of planning, and things like RAM, processor speeds, etc. haven't yet been decided. It's looking more and more like a 2013 release.