So.. I may be completely misunderstand this article, but this is what it says.
http://www.engadget.com/2009/03/06/shocker-retail-core-i7-cpus-caught-using-ddr3-1600-memory/
http://www.engadget.com/2009/03/06/shocker-retail-core-i7-cpus-caught-using-ddr3-1600-memory/