Through a Product Change Notification (PCN), Intel has reported to have changed the CPU cooler for a large number of processors. A similar report was filed in late 2010, when the LGA 775 cooler was changed, likely to reduce costs. The new bundled heatsink has a round profile, compared to the square design of the original. Intel claims that the change is purely cosmetic and that it does not affect its cooling performance. The holes to mount a fan have been made slightly larger. It's possible that Intel has made this decision to technically optimise the design, as well as reduce costs.
The boxed coolers will be bundled with a large number of Xeon, Core, Pentium and Celeron processors, including the i3-3240, i5-3470, i5-3570K and i7-3770K.