Some specs from a leaked slide

X720 X360 Thoughts
32nm SOI 90nm then 65nm now 45nm Runs cooler
4 OoO cores 3 in-order cores More cores, more efficient
4 SMT per core 2 SMT per core More efficiency
3.2GHz max in Turbocore mode 3.2GHz Same but chip could do more per clock
512 KiB L2 cache per core 1024 KiB L2 total More in total, what about snooping?
4 enhanced VMX128 cores 3 enhanced VMX128 cores More is better
80MiB EDRAM 10MiB EDRAM X720 can support 10 32bit 1080p rendertargets
This allows for some FAT gbuffers and Stereo 1080p
EDRAM accessible by CPU, VMX and GPU EDRAM only accessible by GPU This is a game-changer! Now this ultra-high-speed memory is accessible for general purpose (CPU) and stream processing (VMX) it opens up a whole new world of possibilities
Bluray Hardware Decoder No Bluray anything Bluray makes sense
DX11.1 DX9 + extensions All the DX11 goodies plus native Stereo support and DirectCompute …

In general this is just an improved version of the X360 chip. The really exciting thing is the “80MiB EDRAM shared with the GPU” as that could lead to all-new techniques that are unique to the XBOX 720.

The really exciting thing for XBOX 720 is the combination of Kinect2 with 1080p stereo … think about reaching out and touching virtual objects floating around you … actually punching a game character in the face etc.