Intel has said Ivy will be 20% more powerful than the Sandy equivalent. They sport the tri-gate transistors, which can give up to 50% more power savings.
Intel accidentally posted the spec sheet on Ivy's on their website and quickly took it down. Luckily, someone screen captured the table:
The i7-3770K is what you will be looking at. 3.5Ghz base with a 3.9Ghz turbo. This thing is going to scream. I wouldn't be surprised at 5.0Ghz on air with a TDP that low (77w)!