There's actually a five-page thread
over on the Lenovo forums about this. Some interesting stuff was found, but the bottom line is that you have to revert to a previous BIOS edition to get TurboBoost. Also, it doesn't work when the laptop is unplugged (by design, unfortunately). Lenovo forum staff have escalated the issue to engineering, and there will probably be a fix some time soon
The BIOS edition I've been using with TurboBoost successfully is version 1.06
. The download is at the very bottom of the BIOS utility page.