In our endless attempts to squeeze out the last MHz from our processors, some of us have resorted to removing the integrated heat spreaders (commonly refered to as IHS among enthusiasts) on our processors in a bid to improve thermal efficiency, to garner that 2-3 degrees, and trade it for that final 10MHz.
This is not a major roadblock for the AMD processor overclocker since the contact between the heatspreader and the core is made with thermal paste. This is a major problem however when it comes to the Intel LGA socket users. The LGA socket processors use a solder thermal interface between the core and the heatspreader so removing it involves more than just cutting past the rubber linings. In many cases, users have ripped off the entire core as they pry desperately.
Source:LGA Processor Heat Spreader Removal