Here is a paper from 2011 where they claim 7 or 8 bits/cell http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=5873227 http://ieeexplore.ieee.org/xpl/login.j

Here is a paper from 2011 where they claim 7 or 8 bits/cell http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=5873227 http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=587322... This research seems to take program/erase cycles into greater account.