This one is a different i5, but they say it's overclocked at 0.7 something. It's normal clock is 2.3 Ghz clocked to 3.3 Ghz.

http://www.tweaktown.com/news/30114/haswell-imc-could-make-memory-overclocking-fun-again-for-intel-cpu-users-in-the-months-ahead/index.html

I'm guessing around 0.5 or so. I could be wrong.