Intel's X38 Express chipset is the first core logic from the company to utilize an Integrated Heat Spreader (IHS); the copper cap on top of processors like the Pentium 4, D, and Core 2 Duo. An Integrated Heat Spreader helps distribute the heatsink load onto the silicon core below, and conduct the heat the CPU produces out to a larger surface area to aid cooling. Integrated circuits with high heat densities are challenging to cool if the contact surface area between IC and heatsink is small. A heatspreader takes that concentration of heat, and disperses it to a space generally 2-4 times larger. Intel's IHS is made of nickel plated copper.
The Intel X38 Express chipset outputs 26.5W TDP, but given the cooling solutions used on most X38 motherboards, this seems conservative.