FrostyTech posted a review on the Intel FCLGA4-S Core 2 Extreme Reference Heatsink

Ever wonder how Intel's retail heatsinks stack up against the best aftermarket CPU coolers out there? In this review Frostytech will be comparing the Intel FCLGA4-S reference heatsink, which is boxed with retail 45nm Intel Core 2 Extreme QX6850 processors (and others), against one hundred Intel socket 775 heatsinks from every imaginable manufacturer. One notable innovation with Intel's FCLGA4-S reference heatsink is harder to see, a vapour chamber.

Intel FCLGA4-S Core 2 Extreme Reference Heatsink Reviewed