Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
Again, nobody knows for sure. And everybody's hoping for mid/end-july along with the Mountain Lion release.

:)

ps: there are a thousand threads like yours right now...
 
That was what happened last time in 2010. But I think the leap from our 2009 Core 2 Duo to our 2011 i5 Sandy Bridge was greater than what I think we'll be seeing, from 2011 i5 to 2012 i5.
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.