The Atom Renaissance. Windows RT is history – the new entry-level version of the Yoga-series uses Intel's Bay Trail and a full version of Windows 8.1 64-bit. More usage scenarios and more performance also result in a significant drop of the battery runtimes.
http://www.notebookcheck.net/Review-Lenovo-IdeaPad-Yoga-2-11-Convertible.116051.0.html
That's a big drop in battery life from the RT version. I was hoping for 8 hours, but this is too much. :(