Goto speculates that Sony's upgraded processor would feature between 10 and 20 cores (current Cell uses 8) and boast twice the power. Keeping with the Cell -- as opposed to developing a new chipset -- would not only be cost efficient for the company, but it would also likely prove beneficial to manufacturing costs, software development (it'd be a familiar architecture) and backwards compatibility. Remember: although this is from a reputable source, the news is unconfirmed and, given the PS4 is likely many years away, subject to change even if true.
Fun fact: There are approximately 1900 days (over 5 years) between the PS2's March 2000 launch and Sony's E3 2005 unveiling of the PS3.
