browsing around I found this old article from a year ago. Dr T assumed 3ghz @ 200nm scaling.

"If you wanted to match the speed of today's silicon processors, at roughly a 3GHz clock rate, you wouldn't have to go all the way down to 20 or 30 nanometers," says OPEL chief scientist Dr. Geoffrey Taylor. "Heck, you could probably hit that at 200nm." And that's using planar technology, not 3D transistors.

http://www.pcworld.com/article/2033671/breaking-moores-law-how-chipmakers-are-pushing-pcs-to-blistering-new-levels.html

Dug around a little more and found this assumption on 100nm specs prior to completion.

"The 100-nm goal is matched to the state-of-the-art commercial III-V foundry capabilities and will demonstrate the greater than 50x speed improvement together with lower power consumption by a factor ranging from 4 to 10 depending on the application as compared to silicon at smaller nodes."

http://www.poet-technologies.com/poet-technologies-special-strategic-committee-update/

Any thoughts / speculations on how close we really are to this? I dont really understand the next line " by a factor ranging from 4 to 10 "