A whole lot of slides about Carizzo which were posted on Anandtech forums:
http://i.imgur.com/sT1nNVq.jpg?1
http://i.imgur.com/4RQwUDB.jpg?1
http://i.imgur.com/YbP5NdK.jpg?1
http://i.imgur.com/xwdUf6T.jpg?1
http://i.imgur.com/YWQeNBt.jpg?1
http://i.imgur.com/iiFijOJ.jpg?1
http://i.imgur.com/6GFHGEd.jpg?1
It appears Excavator has 5% more IPC than Steamroller but the cores consume 40% less power and are 23% smaller on the same process node.
The whole Carrizo SOC is the same size as Kaveri but does not need a southbridge so will be cheaper to make it appears.